1st BioSoft symposium
Biophysical approaches to understand life at different scales
Forschungszentrum Jülich – 6th November 2014 Within the scope of the graduate school program International Helmholtz Research School in Biophysics and Soft Matter (IHRS BioSoft), the fellows are pleased to organize the first
networking event. We hope that our efforts help to foster a series of events in the near future.
This meeting brings together researchers using quantitative approaches towards the biophysical understanding of different physiological processes essential to life. The sheer complexity of living organisms poses a jumbled puzzle to solve when studying processes like the development of an early embryo or the maturation of pathogenic behaviors. Recent developments in
biotechnology, molecular biology, biochemistry and biophysical modeling have fostered unprecedented approaches to unravel the multidimensional facets of such complex pathways.
Our workshop aims at providing an interdisciplinary platform to bring together the
complementary skills of experimentalists and theoreticians (spanning as many involved fields as possible) in order to understand the role of forces, flow and fluctuations within biological systems. The 7 proposed talks specifically address 3 major themes:
1. Bioadhesion, cytoskeleton and cell motility 2. Tissue growth and morphogenesis
3. Collective behaviors in biological networks
The proposed themes focus on cellular behavior at different scales ranging from the single cell level to multicellularaggregates like tissues, and even encompass complex biological networks.
A major goal is to provide a platform for students and young scientists to present and discuss their work with other students and expert researchers, in order to promote the mutual exchange of ideas and facilitate the development of novel research directions.
Looking forward to seeing in Juelich, Sabyasachi Dasgupta, Guglielmo Saggiorato, Gloria Fabris, and Melanie Balbach
Schedule
9:00 9:10 Introduction to the symposium
9:10 10:05 Biomimetics (T1) A. Roux – Univ. of Geneva (Switzerland)
Mechanics of protein coats in cell membrane traffic 10:05 11:00 Cytoskeleton (T2) J. Guck TU Dresden (Germany)
How cells feel and why that's important 11:00 11:15 Coffee & tea break
11:15 12:15 Cell Adhesion (T3) E. Sackmann TU München (Germany) Physics of Cell Adhesion
12:1514:15 Poster Session @ Lunch 14:15 15:15 Collective Behavior (T4)
P. Silberzan Institut Curie, Paris (France) Imposing and releasing confinement to an epithelium
15:15 16:15 Bionetworks (T5) T. Mora ENS, Paris (France)
Inferring the statistical mechanics of collective phenomena
16:15 16:45 Coffee & tea break
16:45 17:45 Morphogenesis (T6) P. F. Lenne IBDM, Marseille (France) Mechanics of cell contacts during tissue morphogenesis
17:45 18:45 Developmental Biology (T7)
L. Hufnagel EMBL Heidelberg (Germany) BioImaging across scales with lightsheet microscopy: from cells to embryos
18:45 19:00 Valedictory remarks
Talk abstracts
T1. Aurelien Roux
Mechanics of protein coats in cell membrane traffic
Proteins involved in membrane traffic transiently interact with lipid membranes in order to remodel them, i.e. to deform them, cut and fuse them. But lipid membrane are not passive in these processes, they are viscoelastic surfaces which require energy to be remodeled. In this talk I will review a few studies where we show that the elastic energy of the membrane impacts the function of protein assemblies in membrane traffic. In particular, we will show how
membrane tension and rigidity competes with clathrin budding and dynamic fission reactions, and I will show how ESCRT proteins have evolved to deform membranes by buckling.
T2. Jochen Guck
How cells feel and why that's important
While most current biological research focuses on molecular, biochemical aspects of cell
function, we are interested in the mechanical properties of cells and tissue and their importance for biological function. The mechanical strength of cells is largely determined by the
cytoskeleton, an internal polymer hybrid network intricately regulated by many signaling pathways. This cytoskeleton evolves during physiological changes, such as differentiation, is involved in many cellular functions, such as migration, and is characteristically altered in pathologies, including cancer or inflammation. We can exploit the deformability of the cytoskeleton as a link between molecular structure and biological function to sensitively monitor these functional changes using an optical stretcher and a novel, highthroughput microfluidic technique. Our results indicate that the material properties of cells define their function, can be used as an inherent cell marker and could serve as target for novel therapies.
T3. Erich Sackmann
Physics of Cell Adhesion
Cells migrate by ongoing formation of adhesion domains at the leading front and their dismantling at the trailing end. Protruding forces are generated by sequential generation of solitary actin gelation waves protruding form adhesion domains (AD). The AD are formed by interplay of generic and specific interfacial forces and act both as force transmitting feet and biochemical reaction centers controlling actin polymerization and actinmicrotubule crosstalk.
Actin polymerization serves the generation of protrusion forces while microtubules drive the motion of the cell body.
The global polarization of migrating cells is mediated by actin microtubule crosstalk. The short range cell polarization is controlled by the competition of antagonistic GTPase controlled biochemical pathways. that promote actin gelation at the front of migrating cells and AD dismantling at the trailing ends , respectively.
Insight into the actin microtubule crosstalk is gained by magnetic tweezer microrheometry.
Microinterferometry (RICM) serves the observation of adhesion domains and the measurement of adhesion and transmission forces.
T4. Pascal Silberzan
Imposing and releasing confinement to an epithelium
Epithelial tissues, for which cells maintain contacts with their neighbors, exhibit collective behaviors largely controlled by cellcell interactions. In this context confinement and boundary conditions play an important role in the dynamics of these cell assemblies. Interestingly, many in vivo processes, including morphogenesis or tumor maturation, involve small populations of cells within a spatially restricted region. Cells confined on finite, populationsized domains exhibit both collective rotation with stochastic reversals and lowfrequency radial displacement modes. When this boundary condition is removed, we observe the collective migration of these epithelia. In the first stages, the essential characteristics of these collective dynamics in these two situations are well described by the same model in which cells are described as persistent random walkers which adapt their motion to that of their neighbors. However, at late stages, cells in confined epithelia develop a tridimensional structure in the form of a peripheral cell cord at the domain edge. Epithelial confinement by itself is thus observed to induce
morphogeneticlike processes including spontaneous collective pulsations and transition from 2D to 3D.
References:
[1] Deforet, M., Hakim, V., Yevick, H. G., Duclos, G. & Silberzan, P. Emergence of collective modes and tridimensional structures from epithelial confinement. Nat. Commun. 5, 1–9 (2014).
[2] Reffay, M. et al. Interplay of RhoA and mechanical forces in collective cell migration driven by leader cells. Nat. Cell Biol. 16, 217 (2014).
[3] Sepúlveda, N. et al. Collective cell motion in an epithelial sheet can be quantitatively described by a stochastic interacting particle model. PLoS Comput. Biol. 9, e1002944 (2013).
T5. Thierry Mora
Inferring the statistical mechanics of collective phenomena
Collective phenomena are emergent events that cannot simply be explained as a sum of
individual behaviors. They are relevant at many scales in biology, from the collective dynamics of neural networks to the concerted motion of bird flocks. Focusing on these two examples, I will show how the tools and concepts of statistical mechanics, when applied directly to experimental data, can be used to gain insight about the collective behavior of complex biological systems.
T6. Pierre François Lenne
Mechanics of cell contacts during tissue morphogenesis
Cellgenerated forces produce a variety of tissue movements and tissue shape changes. The cytoskeletal elements that underlie these dynamics act at cellcell and cellextracellular matrix contacts to apply local forces on adhesive structures. Using quantitative imaging and force measurements in vivo, we study how cellcell contacts are organized and how subcellular tensile forces are transmitted to drive tissue morphogenesis.
T7. Lars Hufnagel
BioImaging across scales with lightsheet microscopy: from cells to embryos
Developmental processes are highly dynamic and span many temporal and spatial scales. A wholeembryo view of morphogenesis with subcellular resolution is essential to unravel the interconnected dynamics at the varying scales of development, from interactions within cells to those acting across the whole embryo. Bridging scales from the submicron to the millimeter range with a temporal resolution of several seconds (combined with a total imaging time of several hours) not only poses tremendous challenges for modern microscopy methods but also requires powerful computational approaches for data handling, processing and image analysis.
I present a multiview selectiveplane illumination microscope (MuViSPIM), comprising two detection and illumination objective lenses, that allows rapid /in toto/ fluorescence imaging of biological specimens with subcellular resolution.
Campus Map
Posters
01 Nanosecond protein dynamics studied by singlemolecule FRET and a coarsegrained model,
Gabba Matteo
02 Migration of red blood cells in microvessels, Katanov Dinar
03 Depletion interactions induced by fd virus: on the limits of low density and Derjaguin approximation,
Desio Silvia
04 Numerical Study of (Dynamic) Light Scattering by Red Blood Cells in Equilibrium and Flow, Johannes Mauer
05 Added dimensionality: New approaches towards improved cell/chip coupling for multielectrode arrays,
Ullmann Sabrina
06 Macromolecular crowding induces holo α lactalbumin aggregation by converting to its apo form,
Mittal Shruti 07 Role of NAcetylaspartate in Alzheimer disease,
Warepam Marina
08 PAH1 domain is responsible for the
thermodynamic and structural stabilization of hSin3B in low pH condition,
Raj Tauheed Hasan 09 Nhomocysteinylation Induces Different
Structural and Functional Consequences on Acidic and Basic Proteins,
Gurumayum Suraj Sharma
10 Knowledgebased protein structure prediction, Hoffmann Falk
11 Phase Differential Microscopy, a new method for measuring chemotactic fluxes,
Colin Remy
12 Conformational fluctuations of DNA hairpin
loops: dissecting the multiple impacts of macromolecular crowding,
Stiehl Olivia 13 SPIM applications in organismal biology,
Struntz Philipp
14 Mechanical cues during early embryogenesis of C.
elegans,
Fickentscher Rolf 15 Forces and restraints: a bottomup approach to
studying cell shape, Kurniawan Nicholas
16 Phase separation of selfpropelled rods with length bidispersity,
Abkenar Masoud 17 Potassium Binding to Excitatory Amino Acid
Transporters, Kortzak Daniel
18 SMLM Imaging the Cytoskeleton, Hendriks Johnny
19 Local averaging of single particle cryoelectron microscopy data,
Duraisamy Amudha Kumari
20 Structure and Dynamics of HIV1 TAR RNA complex with a small molecule,
Kolar Michal H.
21 Elements and relations of a Life Theory (LT), Opielok Stephan
22 Structural dynamics of a cyclic nucleotide
binding domain during ligand binding, Mukherjee Shatanik
23 Superresolution microscopy provides insights into sea urchin sperm,
Hamzeh Hussein
24 Length matters: hydrophobic mismatch sorts SNARE proteins into distinct membrane domains,
Milovanovic Dragomir 25 Forcing clathrin onto its knees,
Platen Mitja
26 Investigating the crosstalk between GBA1 and GBA2 in Gaucher disease,
Schonauer Sophie 27 Intracellular Calcium fluctuations modulate
directional migration of dendritic cells, Guu Donald
28 Simulation of transport through biological networks,
Denisov Dmitry 29 Dynamic properties of molecular motors moving
along the cytoskeleton, Miedema Daniel
30 Simulation and Modeling for the Reconstruction of Nerve Fibers in the Brain by 3D Polarized Light Imaging,
Menzel Miriam
31 Microrheology study of integrin dependent mechanical properties of fibroblast cells, Klein Jan Fenneke
32 Investigating dynamic processes in pathogenic Acanthamoeba,
SelhuberUnkel Christine
33 Neutron spectroscopic observation of fast motions in ADH With and withoud NAD in aqueous solution,
Michael Monkenbusch
34 Artificial Tissue, ultrasoft elastomers for cell mechanical investigation,
Heinrichs Viktor
35 Understanding and controlling cellular
networks: Multicellular in vitro models for heart tissue,
Benjamin Wolters
36 Positive charged lipid bilayer formation on gold for neuronal cell culture,
Choi SungEun
37 Monitoring dopaminergic signalling in the retina with genetically encoded sensor proteins, Sieben Anna
38 A Novel Fusogenic Drug Delivery System, Braun Tobias
39 The antimicrobial peptide [KIGAKI]3 perturbs lipid membranes,
Schulte Marianne
40 Solid State NMR Spectroscopy: Investigation of the core arrangement in the prion domain of Sup35NM S17R mutant,
Uluca Boran
41 Ab initio protein structure modeling with density map,
Wang Zhe
42 PHAT: PHysarum Analysis Tool, Dirnberger Michael
43 Structure and dynamics of human Nedd41 WW3* domain,
Panwalkar Vineet
44 Flow and Diffusion in ChannelGuided Cell Migration,
Marel AnnaKristina 45 Supported lipid bilayer with incorporated fusion
proteins: a platform for studying cellcell contact,
Afanasenkau Dzmitry
46 Sorting cryoEM images into classes of similar molecular conformations,
Spiegel Michaela
47 Mesoscale Modelling of Microparticle Flow in Deterministic Lateral Displacement Devices, Henry Ewan
48 Silicon Nanowire Structures For Biosensing, Pud Sergii
49 Simulation of singlemolecule fluorescence data with regard to Amyloid beta 42 detection, Schneider Mario
50 Investigation of DPPCMembranes in the gel phase and its phase transition in Molecular Dynamics Simulations
Kowalik Bartosz 51 The acinar cage: molecule exchange and
mechanical stability of breast glands are determined by basement membranes, Aljona GaikoShcherbak, Gloria Fabris
52 Splinelike interpolation in particle tracking microrheology,
Tamás Haraszti
53 Higherorder architecture of rhodopsin in photoreceptors,
Anne V. Schulze
54 Effect of hydrophobic mismatch and rigidity of proteins on the cluster formation of
transmembrane proteins in biomembrane, Hamidreza Jafarinia
Poster abstracts
P1. Matteo Gabba
Institute of Complex Systems 5 Forschungszentrum Jülich
Nanosecond protein dynamics studied by singlemolecule FRET and a coarse
grained model
Well pronounced interdomain movements in 3Phosphoglycerate kinase (PGK) are assumed to be crucial for the reversible phosphor transfer reaction catalyzed by this enzyme during
glycolysis. Using a cysteine double mutant with fluorescent dyes attached at the distal ends of each domain of PGK from yeast [1], we performed singlemolecule Förster Resonance Energy Transfer (smFRET) experiments[2]. The fast dynamics of the protein were simulated with an elastic network (EN) under a Multiparticle Collision Dynamics (MPC) approach, combined with an accessible volume (AV) description of the dye [3]. 2Dplots of the FRETefficiency versus the donor lifetime [4] show that PGK is a highly flexible system with interdomain dynamics
spanning from nanoseconds up to milliseconds. Here, slow interconversion between an
extended state and a compact conformation of the domains take place. The internal dynamics of the compact state is faster than milliseconds. Starting from the compact state, hinge bending brownian fluctuations bring the ligandfree protein in the catalytically competent state. The character of this functional motion is encoded in the structural topology of PGK as shown by normal mode analysis (NMA). Upon addition of the substrates the expanded state depopulates, with a population shift mechanism selecting the compact conformation which better allows the functional relevant motions. The timescale of the interdomain motions is recovered by means of the mesoscale hydrodynamics simulation.
[1] T. Rosenkranz, R. Schlesinger, M. Gabba, J. Fitter, ChemPhysChem, 12, 704710, 2011.
[2] Matteo Gabba, Simon Poblete, Daryan Kempe, Antonie Schöne, Tina Züchner, Gerhard Gompper, Jörg Fitter, Biophysical Journal, Vol. 106, Issue 2, p253a
[3] S. Sinbert et al., JACS, 133, 24632480, 2011.
[4] E. Sismakis, A. Valeri, S. Kalinin, P.J. Rothwell, and C.A.M. Seidel, Methods in Enzymology, 475, 455514, 2010.
P2. Dinar Katanov
Institute of Complex Systems 2 Forschungszentrum Jülich Migration of red blood cells in microvessels
Blood flow resistance in microcirculation is affected by the distribution and migration of red blood cells (RBCs) in flow. RBCs in microvessels migrate toward the vessel center due to hydrodynamic interactions with the walls leading to a cellfree layer near the walls and to a decrease in blood flow resistance. However, the position of RBCs in flow is disturbed at vessel bifurcations and branches resulting in an increase of the flow resistance. Using mesoscopic hydrodynamics simulations of blood flow, we study the migration of RBCs toward the center of cylindrical vessels and monitor a change in the flow resistance. The RBC migration is
investigated for different flow rates, tube diameters, hematocrit values, and RBC aggregation interactions. Our results show that the migration for different flow rates can be well described by a master curve using a proper time scale. RBC aggregation interactions lead to a significant decrease in flow resistance at low flow rates. Finally, the effect of flow disturbance at vessel branching sections on blood flow resistance is quantified. These results are also relevant for flow of a suspension with other deformable particles.
P3. Silvia Desio
Institute of Complex Systems 3 Forschungszentrum Jülich
Depletion interactions induced by fd virus: on the limits of low density and Derjaguin approximation
Depletion interactions can determine the phase behavior of bicolloidal or more complex suspensions, by which they play an important role in crowded biological systems as well as in colloidal formulations used in technical applications. The theory of Depletion interaction was first formulated in terms of pairwise potentials by Asakura and Oosawa in the ’50 for the case of large colloidal spheres dispersed in a solution of noninteracting depletants, where the colloidal particles interact among each other and with the depletants solely by excluded
volume, while the depletants are treated like an ideal gas (low density approximation) and they are much smaller than the spheres (Derjaguin approximation). The AsakuraOosawa
description has been proven right by many experiments and numerical calculations within its limits of low density and Derjaguin approximation. In this study we were exploring the limits of these approximations by willingly violating them for the case of Depletion potentials induced
by rodlike depletants between a spherical probe and a planar wall. By means of total internal reflection microscopy (TIRM), we measured the Depletion potentials profiles between four differently sized probes in the micrometer range (1mm4mm in diameter) and a planar wall which were induced by fd virus rods. The rods have a length L=880 nm, consequently we varied the size ratio L/R from 0.44 to 1.76. We applied suspensions with virus concentrations ranging from 0.06 mg/ml (just below the overlap value c*=0.07 mg/ml) up to 1 mg/ml (almost 15c*) to induce Depletion between the probes and the wall. We find that the low density
approximation and the Derjaguin approximation hold surprisingly far beyond the expected limits. The low density approximation holds up to rod concentrations of approximately six to seven times larger than the overlap concentration, while Derjaguin approximation is violated only if the particle diameter is of the order of the rod length or smaller.
P4. Johannes Mauer
Institute of Complex Systems 2 Forschungszentrum Jülich
Numerical study of (dynamic) light scattering by red blood cells in equilibrium and flow
We investigate light scattering properties of red blood cells in diffusion and flow conditions.
The simulation results are expected to deepen the understanding of specific types of blood flow.
P5. Sabrina Ullmann
Institute of Complex Systems 6 Forschungszentrum Jülich
Added dimensionality: New approaches towards improved cell/chip coupling for multielectrode arrays
Multielectrode arrays (MEAs) are gaining increasing importance for the investigation of signalling processes between electrogenic cells and the study of bionetworks. In contrast to patch clamping, the current gold standard for the investigation of cellular signals, MEAs are noninvasive and enable parallel, multisite recording. Efficient cellchip coupling for robust and longterm electrophysiological recording and stimulation, however, still remains a challenge. A possible approach for the improvement of the cellelectrode contact is the utilization of threedimensional structures. Since the formation of a tight cell
membrane/electrode contact is a prerequisite for a high sealing resistance and high signal amplitude, we aim to understand the geometrical conditions that facilitate a tight and stable interface. Here, we investigate various different designs such as mushroomshaped 3D
electrodes and nanocavities for their capabilities with respect to the recording of cellular signals.
P6. Shruti Mittal
Dr. B. R. Ambedkar Centre for Biomedical Research University of Delhi Macromolecular crowding induces holo lactalbumin aggregation by α converting to its apo form
Macromolecular crowding has been shown to have an exacerbating effect on the aggregation propensity of amyloidogenic proteins; while having an inhibitory effect on the non
amyloidogenic proteins. However, the results concerning aggregation propensity of non
amyloidogenic proteins have not been convincing due to the contrasting effect on holo α lactalbumin (holoLA), which despite being a nonamyloidogenic protein was observed to aggregate under crowded conditions. In the present study, we have extensively characterized the crowdinginduced holoLA aggregates and investigated the possible mechanism
responsible for the crowdinginduced aggregation process. We discovered that macromolecular crowding results in the loss/reduction in the calcium binding affinity of the holoLA leading to aggregate formation. In addition, calcium is observed to act as a chaperone capable of inhibiting and dissociating crowdinginduced holoLA aggregates. The study has a direct implication to Alzheimer Disease as the results invoke a new mechanism to prevent A fibrillation.β
P7. Marina Warepam
Dr. B. R. Ambedkar Centre for Biomedical Research University of Delhi Role of NAcetylaspartate in Alzheimer disease
Alzheimer’s disease (AD), one of the most common neurodegenerative disorder is well characterised by accumulation of a highly ordered protein aggregates in brain. Recently, with the advent of a technique (proton magnetic resonance spectroscopy) for monitoring changes in levels of brain metabolites during the disease progression, a decrease in NAcetylaspartate (NAA) and an increase in Myoinositol (mI) levels have been most consistently detected in brains of AD patients. On such grounds, both of them were often regarded as a valuable marker
for diagnosis of AD. A relationship between the formation of protein aggregates and changes in level of these two markers has not been studied. Therefore, it is important to investigate their roles on protein aggregation. In this study, we have investigated the effect of NAA and mI on aggregation profile of an aggregation model protein, carbonic anhydrase. Here, we found that while NAA with increasing concentration is able to inhibit aggregation of the protein, mI affect only the rate of aggregation. However, when mI is titrated with NAA, rate as well as magnitude of the protein aggregation is reduced. This suggests that importance of NAA level in brain cells AD patients to control the deposition of protein aggregations.
P8. Tauheed Hasan
Dr. B. R. Ambedkar Centre for Biomedical Research University of Delhi PAH1 domain is responsible for the thermodynamic and structural stabilization of hSin3B in low pH condition
Human Sin3B (hSin3B), is a scaffold protein that binds to different transcription factors and regulate transcription. It consists of six conserved domains that includes four Paired
Amphipathic Helices (PAH 14), one histone deacetylase interaction domain (HID) and one highly conserved region (HCR). Sin3 has no DNA binding domain of its own; therefore it requires DNA binding transcription factors on PAH domains of Sin3 to regulate transcription of genes. Recent advances have proved that hSin3B is a stress protein and gets upregulated in various stress condition such as DNA damage, oncogenic stress, oxidative stress and low pH condition. As each of the PAH domains of hSin3B have different physiochemical properties such as pI (isoelectric point of protein) and hydropathy index. Therefore it might be possible that the PAH domains shows different thermodynamic and structure stability in stress condition. In the present communication we have investigated the effect of extreme pH on structure and thermodynamic stability of the different PAH domains of hSin3B. Our major finding is that PAH1 is structurally and thermodynamically more stable at pH 4 beyond which the protein gets unfolded whereas PAH2 and PAH3 domains get destabilized in low pH condition. This study indicates that PAH1 domain might responsible for stabilization of hSin3B in extreme of pH condition not the whole protein.
P9. Suraj Sharma Gurumayum
Dr. B. R. Ambedkar Centre for Biomedical Research University of Delhi Nhomocysteinylation induces different structural and functional consequences on acidic and basic proteins
One of the proposed mechanisms of homocysteine toxicity in human is the modification of proteins by the metabolite of Hcy, homocysteine thilolactone (HTL). Incubation of proteins with HTL has earlier been shown to form covalent adducts with amino group of lysine residues of ε protein (called Nhomocysteinylation). It has been believed that protein Nhomocysteinylation is the pathological hallmark of cardiovascular and neurodegenerative disorders as
homocysteinylation induces structural and functional alterations in proteins. In the present study, reactivities of HTL towards proteins with different physicochemical properties and hence their structural and functional alterations were studied. We found that N
homocysteinylation has opposite consequences on acidic and basic proteins suggesting that pI of the protein determines the extent of homocysteinylation, and the structural and functional consequences due to homocysteinylation. Mechanistically, pI of protein determines the extent of Nhomocysteinylation and the associated structural and functional alterations. The study suggests the role of HTL primarily targeting acidic proteins in eliciting its toxicity that could yield mechanistic insights for the associated neurodegeneration.
P10. Falk Hoffmann
Institute of Complex Systems 6 Forschungszentrum Jülich Knowledgebased protein structure prediction
We use the basinhopping approach to global optimization for protein structure prediction. The basinhopping approach is based on Monte Carlo with minimization and has already been employed to find the global minimum of peptides. However, for larger peptides and proteins the effective sampling of the highdimensional conformational space has remained a challenge, thus necessitating the development of a guided basinhopping approach. One such approach is to use NMR chemical shifts as structural restraints as they facilitate to determine nearnative structures with very high accuracy.
Furthermore, we implemented knowledgebased Monte Carlo moves which allow us to fold proteins from their primary to their tertiary structure without any restraints. Additionally, we also work on knowledgebased moves which are based on Ramachandran plots. We create a
plot for every amino acid and change the dihedral angle at every move according to the Ramachandran plot of the corresponding amino acid.
P11. Remy Colin
AG Sourjik Max Planck Institute for Terrestrial Microbiology
Phase Differential Microscopy, a new method for measuring chemotactic fluxes
Recent developments in Fourier image analysis have significantly improved the statistics in measuring the dynamics of microorganisms. We designed a new image analysis method which allows the measurement of collective drifts, such as chemotactic drifts, with an unprecedented resolution (down to a few thousandths of the bacterial swimming speed), using video
microscopy. The method is based on analyzing the Fourier components of the images of the film (more precisely their phase – hence the technique’s name) and does not require to actually track the cells, avoiding the errors specific to particle tracking. We applied this method to measuring the chemotactic velocity of populations of E. coli in response to linear gradients of attractants.
The gradient is generated by connecting two large reservoirs with different attractant
concentrations through a small channel. The motion of the bacteria is investigated in the center of this channel, where a linear gradient of the chemical forms. We were able to resolve both the linear and logarithmic gradient sensing regimes at respectively low and large concentrations of attractant, consistently with previous works. We derive a prediction for the chemotactic flux from the singlecelllevel model for the chemotactic response, in excellent agreement with our measurements.
P12. Olivia Stiehl
Experimental physics IUniversity of Bayreuth
Conformational fluctuations of DNA hairpinloops: dissecting the multiple impacts of macromolecular crowding
Biochemical reactions in crowded fluids differ strongly from those in dilute solutions. Both, excluded volume interactions with surrounding macromolecules and an enhanced rebinding of the reaction partners due to a crowdinginduced viscoelasticity and
subdiffusion have been predicted to shift chemical equilibria towards the associate state.
Using fluorescence correlation spectroscopy and UV absorption, we tested the stochastic opening and closing of singlestranded DNA hairpinloops under crowded conditions. Our experiments reveal that crowding not only slows down the kinetics but also increases the steadystate fraction of closed hairpins significantly [1].
Exploiting varying degrees of diffusion anomalies with the same crowder and similiar occupied volume fractions, we could dissect the differential contributions of macromolecular crowding:
Excluded volume already leads to an enhanced fraction of closed hairpins but this effect is strongly increased in crowded fluids that feature anomalous diffusion [2].
[1] O. Stiehl, K. WeidnerHertrampf and M. Weiss: Kinetics of conformational fluctuations in DNA hairpinloops in crowded fluids. New J. Phys. 15 (2013) 113010.
[2] O. Stiehl, K. WeidnerHertrampf and M. Weiss: Dissecting the multiple facets of
macromolecular crowding on the diffusion and conformation of DNA hairpinloops, submitted (2014).
P13. Philipp Struntz
Experimental physics I University of Bayreuth SPIM applications in organismal biology
Fluorescence imaging is a powerful tool for investigating the mechanisms of embryogenesis.
However, common microscopy techniques like confocal imaging have the great disadvantage of high photobleaching which can interfere with the development of the embryo and hinder long
term acquisitions of the sample due to signal loss and phototoxicity.
To overcome these limitations we have designed and constructed a fully automated single
plane illumination microscope (SPIM) for imaging embryos of the nematode Caenorhabditis elegans in the early stages of development [1]. The combination of rapid widefield detection with optical sectioning and reduced bleaching allows longterm, threedimensional in vivo imaging with a high spatiotemporal resolution. Cellmovement and arrangment can be observed by imaging GFPlabeled nuclei of the embryo while SPIMFCS measurements
quantify the dynamics of labeled molecules in the threedimensional environment of the living organism.
SPIM therefore provides several applications within one setup and hence is a powerful tool for examining dynamics and pattern formation in organismal biology.
[1] Rolf Fickentscher, Philipp Struntz & Matthias Weiss: Mechanical cues in the early embryogenesis of Caenorhabditis elegans. Biophys. J, 105:1805 – 1811 (2013)
P14. Rolf Fickentscher
Experimental physics I University of Bayreuth
Mechanical cues during early embryogenesis of C. elegans
The impact of biochemical signaling on developmental processes has been studied intensively.
To elucidate the role of mechanical cues during embryogenesis in the model organism
Caenorhabditis elegans, we have used a custommade light sheet microscope, which allowed for threedimensional longterm imaging of living organisms with high spatiotemporal
resolution [1]. We have imaged and analyzed C. elegans embryos in which nuclei or the plasma membrane were fluorescent. To obtain information on the migration of nuclei during early embryogenesis, we developed a specifically adapted tracking algorithm. In addition, we
extracted information about cellvolumes, shapes and cell arrangements via a new segmentation algorithm based on seeded region growing. Following cell divisions and migration in three dimensions, we compared different individuals. Small deviations of cell trajectories indicated a robust cellular arrangement process. A simple mechanical model revealed that early cell organization is determined by the cells’ quest for a position with least repulsive interactions of their environment. The model also predicts key features of the developing tissue in agreement with experimental observations.
[1] R. Fickentscher, P. Struntz & M. Weiss: Mechanical cues in the early embryogenesis of Caenorhabditis elegans. Biophys. J, 105:1805 – 1811 (2013)
P15. Nicholas Kurniawan
Biological Soft Matter FOM Institute AMOLF
Forces and restraints: a bottomup approach to studying cell shape
Many important cellular functions, such as control of cell shape, mechanics, division, and migration, are governed by the dynamics of the cytoskeleton and its interactions with the cell membrane. To achieve this wide variety of functions, these interactions are highly regulated, both spatially and temporally, by a host of molecular players, making it difficult to disentangle the specific biochemical pathways. To address this problem, we have taken a bottomup
approach: an active, crosslinked cytoskeletal network in controlled confinements. We find that,
in microchambers, myosin motors contract actin polymer networks to clusters with a scalefree size distribution. The switch between local and global contraction is governed by network percolation and restructuring by fascin crosslinkers. In cellsized deformable liposomes, addition of fascin results in bundling of actin filaments, which can dramatically deform
liposomes and form filopodialike protrusions. Myosin motors further induce a variety of active structural reorganizations of actin bundles. Anchoring of actin to the membrane led to the formation of cortexlike structure on the inner surface of the membrane. These results provide valuable insights into the interplay between active intracellular forces and environmental confinement in determining cell shape.
P16. Masoud Abkenar
Institute of Complex Systems 2 Forschungszentrum Jülich
Phase separation of selfpropelled rods with length bidispersity
The collective behavior of microswimmers has gained considerable attention in the recent years.
Examples of microswimmers span from biological cells to nanobots. Here, we propose a model for selfpropelled rods in two dimensions that interact with a physical interaction. We model each rod by a number of beads to calculate the rodrod interactions using a capped interaction potential [1,2].
Polydispersity is inevitable in most experimental studies of microswimmers. For the first time, we study the effect of geometric bidispersity in active rod suspensions, where the system is composed of short and long rods [3]. Depending on the density and the lengths of each rod species, we find a rich phenomenology for the bidisperse system: a disordered phase at low densities, a segregated phase with clusters of only the long rods, a phase where both long and short rods form giant clusters, and a "remixed" phase at very high densities. We also report on a phase where the presence of short rods imposes clustering of long rods in an otherwise
homogeneous longrod suspension.
[1] Yang et al., PRE 82, 031904 (2010).
[2] Abkenar et al., PRE 88, 062314 (2013).
[3] Abkenar et al., in preparation (2014).
P17. Daniel Kortzak
Institute of Complex Systems 4 Forschungszentrum Jülich Potassium binding to excitatory amino acid transporters
Excitatory amino acid transporters (EAATs) terminate glutamatergic synaptic transmission and prevent extracellular glutamate concentrations from reaching neurotoxic levels. EAATs couple the uptake of glutamate to the cotransport of three Na+ and one H+ and to the countertransport of one K+. They are not only secondary active transporters, but also anionselective channels.
The K+dependent reactions are assumed to determine the rate of glutamate transport and represent promising pharmacological targets to modify EAAT function in disease conditions.
Here we combine molecular dynamics simulations of a prokaryotic EAAT homologue and patchclamp recordings to resolve how K+ binds to mammalian EAATs.
Our simulations predict three distinct K+ binding sites, which we are currently validating experimentally. We propose that K+ and one Na+ ion share one overlapping binding site and that further, possibly transient, binding sites are responsible for K+dependent glutamate transport.
P18. Johnny Hendriks
Institute of Complex Systems 4 Forschungszentrum Jülich SMLM Imaging the cytoskeleton
The cytoskeleton is built from structural elements (fibers, tubules) on the order of 10nm in width. As such it is an interesting subject of study for Single Molecule Localization Microscopy (SMLM).
P19. Amudha Kumari Duraisamy
Institute of Complex Systems 3 Forschungszentrum Jülich
Local averaging of single particle cryoelectron microscopy data
Single particle cryoEM is a powerful technique to study the structure of biomolecular
assemblies that are often large, flexible and conformational heterogeneous. Most of the density maps obtained from cryoEM experiments are limited in resolution by this conformational
heterogeneity. Improving the resolution of the density maps, thus, requires to account for the structural heterogeneity. In principle, the resolution can be reached to the atomic level,
if the images of the structures are aligned accurately [1].
In the biological macromolecules, the conformational motions leads to global structural changes, however there are often rather rigid domains. Those rigid domains could be used to align and average the density to reach higher resolution. This is analogous to NCS averaging used to improve the phase information in the field of XRay crystallography [2]. An algorithm is presented to average rigid domains and to improve the resolution of cryoEM density maps.
[1] Henderson. R, Q. Rev. Biophys. 28 171193 (1995).
[2] Kleywegt. G and Read. R, Structure 5 15571569 (1997).
P20. Michal H. Kolar
Institute of Neuroscience and Medicine Forschungszentrum Jülich
Structure and dynamics of HIV1 TAR RNA complex with a small molecule
Transactivating response element is a short noncoding viral RNA, which regulates
transcription. Classical allatom MD simulations of TARinhibitor complex are analyzed and compared with NMR data.
P21. Stephan Opielok
FU Berlin
Elements and relations of a Life Theory (LT)
I propose a general theory about the evolving and nature of life. It seems to be based as a rule on interaction between symmetry and asymmetry (~ stability and flexibility) for equilibration.
In that kind of multidisciplinary research is these study more generalize, fundamental, extended and interconnect to previous attempts to explain the question what is life.
Finally the data of this exploration show that nature of living systems is predictable by suitable methods for measurement like e.g. spectroscopy and probability.
As a result, the way of life follow the principle of stationary friction by essential level of sufficiency energy use.
Further informations under www.researchgate.com and google/author.
P22. Shatanik Mukherjee
Molecular Sensory Systems Forschungszentrum caesar Bonn
Structural dynamics of a cyclic nucleotidebinding domain during ligand binding
Protein functions rely on protein motions. Protein structures, obtained with Xray diffraction or NMR, reveal mostly static pictures and do not directly reveal structurefunction relations. To connect structural changes of proteins with function, protein motions have to be analyzed in real time.
I have analyzed an isolated bacterial cyclic nucleotidebinding domain (mlCNBD) to study the dynamics of receptorligand complex formation. cAMP binds to mlCNBD, resulting in a conformational change. Recent kinetic and NMR studies indicate that these structural transitions follow the “inducedfit” mechanism. However, the detailed mechanism of these structural rearrangements leading to channel activation remains elusive.
Transient Electron Paramagnetic Resonance (trEPR) spectroscopy was used to resolve the dynamics of mlCNBDcAMP complex formation. Cysteine residues were introduced at
different sites in the protein to allow labeling with a paramagnetic reagent. Binding of cAMP to the labeled mutants is rapidly initiated either via photolysis of a cagedcAMP or through a micromixer. The trEPR data reveals that protein undergoes millisecond time scale motions.
Collating data across the whole protein will enable us to reconstruct the steps from the apo to the holo state of the protein, thereby, answering whether “inducedfit” mechanism follows a concerted or sequential path from during conformational rearrangement.
P23. Hussein Hamzeh
Minerva Research Group Forschungszentrum caesar Bonn
Superresolution microscopy provides insights into sea urchin sperm
Sea urchin sperm rely on chemotaxis to find their way to the egg cells of their own species within the vast ocean. Stochastic Optical Reconstruction Microscopy (STORM) and Stimulated Emission Depletion (STED) microscopy are employed to investigate the motility and
distribution of proteins that are involved in the chemotactic signaling pathway. One of those proteins is the membranebound guanylyl cyclase, which plays a key role in the chemotaxis of the sea urchin Arbacia punctulata. Our analysis will provide invaluable insight into
understanding chemotaxis at the molecular level.
P24. Dragomir Milovanovic
Department of Neurobiology Max Planck Institute for Biophysical Chemistry Length matters: hydrophobic mismatch sorts SNARE proteins into distinct membrane domains
The clustering of proteins and lipids in distinct microdomains is emerging as an important principle for the spatial patterning of biological membranes. Such domain formation can be the result of hydrophobic and ionic interactions with membrane lipids as well as of specific protein
protein interactions. Using plasma membraneresident SNARE proteins as model, we now show that cholesterolinduced hydrophobic mismatch between the transmembrane domains and the membrane lipids not only suffices to induce clustering of proteins, but can also lead to the segregation of structurally closely homologous membrane proteins in distinct membrane domains. Domain formation is further finetuned by interactions with polyanionic
phosphoinositides and proteins. Our findings demonstrate that the structural organization of membranes is governed by a hierarchy of interactions with hydrophobic mismatch emerging as one of the fundamental physical principles.
P25. Mitja Platen
3rd Institute of Physics Georg August University Göttingen Forcing clathrin onto its knees
The assembly of triskelions (clathrin monomers) into a planar clathrin lattice is novel and assumingly of high value for nanotechnological approaches. Hence, a thoroughly
characterization of its properties is crucial.
In this study we are investigating the mechanics of and the triskelion orientation within these 2D lattices, using atomic force microscopy (AFM). Furthermore, we are identifying changes in the clathrin lattice caused by the absence of its natural
occurring light chains. This, in addition, contributes to the discussion about the light chain’s overall function, which might be the stabilization of the triskelion’s kneejoints.
P26. Sophie Schonauer
Minerva Research Group Forschungszentrum caesar Bonn
Investigating the crosstalk between GBA1 and GBA2 in Gaucher disease
The betaglucosidases GBA1 and GBA2 both degrade glucosylceramide to glucose and
ceramide. Mutations in the GBA1 gene cause Gaucher disease with different clinical subtypes in humans and mice. However, no genotypephenotype correlation has been identified so far. Our results reveal a crosstalk between GBA1 and GBA2 in patients suffering from Gaucher disease, which might help in understanding the different phenotypes.
A crosstalk between GBA1 and GBA2 was analyzed in dermal fibroblasts from Gaucher disease and control patients on an expression and activity level.
Quantitative realtime PCR experiments and Western blot analyses indicated that GBA2 mRNA and protein levels were similar between control patients and patients carrying a mutation in GBA1. Our fluorescencebased betaglucosidase activity assay revealed that not only GBA1, but also GBA2 activity was dramatically decreased in Gaucher disease patients. This effect could partially be rescued by overexpressing hGBA1.
These results reveal a crosstalk between GBA1 and GBA2 on the activity level. Our findings add a new aspect to the complex nature of Gaucher disease and present an emerging target for its treatment.
P27. Donald Guu
Molecular Sensory Systems Forschungszentrum caesar Bonn
Intracellular Calcium fluctuations modulate directional migration of dendritic cells
Actin cytoskeletal dynamics and cell polarization are essential requirements for directional migration of dendritic cells (DCs) in the course of an efficient immune response. Pathogen encounter induces DCs to upregulate their expression of costimulatory molecules and their chemokine receptor CCR7 enabling them to migrate to draining lymphoid organs. Although Calciumsignalling processes have long been known to play important roles in regulating cell migration, in DCs the intracellular Calcium dynamics, their spatiotemporal coordination, and their interplay and integration with other migratory signals remain largely unknown. By the use of highresolution video microscopy and a fluorogenic Calciumsensitive dye we show that the chemokines CCL19 and CCL21 both induce a strong increase in intracellular Calcium levels of LPSstimulated DCs in vitro. Interestingly, we found that DCs display intracellular Calcium
oscillations which might be necessary to initiate directional migration and cell steering in a chemokine gradient. Furthermore we observed, that chemotaxis of DCs in threedimensional collagen gels is strongly abrogated when intracellular Calcium levels were reduced by the use of BAPTAAM chelating agent. Although the underlying mechanism remains unidentified, these data point to the fact that spatiotemporally coordinated calcium gradients are important in orchestrating directional migration of DCs.
P28. Dmitry Denisov
Soft Matter group University of Amsterdam
Simulation of transport through biological networks
The transport of organelles and proteins is of vital importance for living cells. Besides passive transport by diffusion, active transport by molecular motors hopping over the cytoskeleton network is crucial for the survival of cells. We performed simulations using the Totally Assymetric Exlusion Process (TASEP), a paradigmatic model for nonequilibrium transport, to model the dynamics along the microtubule network. We found that the rules at the intersection of the network seem to be the key factor for the formation of traffic jams along the microtubule segments. The rate at which motors at crossing continue along the same microtubule or switch to the other microtubule appears to determine for the transport along the network. We found
three different regimes of motor propagation through network depending on the average motor density. For example, for medium global densities the motor distribution through the network can be highly inhomogeneous and lead to a huge reduction of the transport current through the system, when larger part of the network will be in ‘virtual’ traffic jam.
P29. Daniel Miedema
Soft Matter group University of Amsterdam
Dynamic properties of molecular motors moving along the cytoskeleton
We have developed an advanced analysis technique to extract quantitative motility parameters from the image sequences of (TIRF) microcoscopy of in vitro motility assays in an automated way.
P30. Miriam Menzel
Institute of Neuroscience and Medicine 1 Forschungszentrum Jülich
Simulation and modeling for the reconstruction of nerve fibers in the brain by 3d polarized light imaging
3D Polarized Light Imaging (3DPLI) is a neuroimaging technique that is able to reconstruct the threedimensional pathways of nerve fibers in postmortem brains at the micrometer scale. By transmitting polarized light through histological brain sections in a polarimeter, the
birefringence of the nerve fibers is measured, thus revealing their spatial orientation. To learn more about the interaction of polarized light with brain tissue and to improve the fiber reconstruction, two complementary
simulation approaches have been developed that simulate different fiber constellations and compare the measured fiber orientations with the underlying fiber model.
The first simulation approach uses the Jones matrix calculus to simulate the intrinsic
birefringence of the myelin sheaths which surround the nerve fibers. The fibers are generated in a 3D volume, discretized into small voxels, and transformed into a 3D vector field which indicates the orientation of the optic axes in the birefringent myelin sheath; the fibers are simulated with axial optic axes (macroscopic model) as well as radial optic axes (microscopic
model). In order to compute a synthetic 3DPLI image series, each myelin voxel is represented by the Jones matrix of a rotated wave
retarder. The optical resolution of the polarimeter is simulated by applying blurring and rescaling to the resulting image series. The simulation of different fiber constellations has shown that the microscopic model transforms into the macroscopic model if the optical resolution of the polarimeter exceeds the diameter of single fibers. Thus, for lower optical resolutions, the fibers can be assumed to be uniaxially
birefringent with the optic axes pointing in direction of the fibers. Another simulation approach uses a massively parallelized 3D Maxwell Solver to investigate other optical tissue properties.
The fibers and the surrounding tissue are simulated as homogeneous isotropic materials with different refractive indices. By discretizing Maxwell's equations on a spatial grid, the electric field components of the
transmitted light are calculated. The simulation of different fiber constellations has shown that the samples exhibit form birefringence and diattenuation, which reveals additional information about the spatial orientation of the fibers. Furthermore, it is possible to distinguish between different fibre constellations by the amount of scattered light. The presented simulation methods are valuable tools to better understand the interaction of polarized light with brain tissue and help to improve the reconstruction of the spatial fibre orientations by 3DPLI.
P31. Fenneke Klein Jan
Institute of Experimental Physics Ulm University
Microrheology study of integrin dependent mechanical properties of fibroblast cells
Physical forces are increasingly recognized as an important biological signal. The protein family of integrins are a key element in force sensing, functioning as a bidirectional force signalling protein. They link the cytoskeleton and the extracellular matrix, giving the cells the opportunity to respond to force by adapting the cytoskeletal filaments. However, how the different integrins cooperatively modulate the force response of the cytoskeleton is not understood.
To study the crosstalk between integrins avb3 and a5b1 we use mouse embryonic fibroblasts that express only the single integrin or a combination of both. We focused on the local mechanical properties of isolated cytoskeletal filaments using microrheology. Studying the influence of these integrins under static and shear stress conditions, and the effect of distinct substrate rigidity levels.
Results show that the avb3 integrin is responsible for reinforcing the network under shear stress conditions. Without this integrin (a5b1 fibroblasts) the network is less elastic with a decreased elastic modulus under shear stress. While shear stress did not influence the elasticity of the other cell types. The substrate rigidity did not affect the elasticity of the cell types a5b1 and avb3a5b1.
P32. Christine SelhuberUnkel
Biocompatible Nanomaterials University of Kiel
Investigating dynamic processes in pathogenic Acanthamoeba
Acanthamoeba castellanii is a human pathogenic parasite that is widespread in our water reservoirs. It can, upon contact with the human eye, cause a severe keratitis. 90% of the patients with this painful disease are contact lens users, who got infected due to wrong contact lens care.
Through small lesions of the outermost epithelial cell layer, the amoebae reach the cornea and start to destroy target cells by an extracellular killing mechanism. A crucial first step during this killing process is the adhesion between an Acanthamoeba and a target cell. This initial contact is supposed to be mediated by carbohydrates. Subsequently, intracellular granules move towards the contact site and release poreforming molecules. These poreforming molecules finally destroy the membrane of target cells.
In our work we aim at understanding the biophysical processes involved in targetcell killing:
we study the “killing kiss” between Acanthamoeba and target cells from their initial adhesion to intracellular transport processes and to target cell death. In particular, studying intracellular motion in Acanthamoeba is highly interesting, as Acanthamoebae are extremely motile, change their shape, and show fast intracellular motion. The final goal of our studies is to receive a comprehensive biophysical picture of Acanthamoeba pathogenicity.
P33. Michael Monkenbusch
Jülich Centre for Neutron Science 1 Forschungszentrum Jülich
Neutron spectroscopic observation of fast motions in ADH with and without
NAD in aqueous solution
P34. Victor Heinrichs
Institute of Complex Systems 1/7 Forschungszentrum Jülich
Artificial tissue, ultrasoft elastomers for cell mechanical investigation
Cell morphology and protein expression are strongly influenced by the elasticity of cell
environment. For investigation of cell mechanics, an elastic and biocompatible model substrate
“artificial tissue” with precisely properties is required. Crosslinked polydimethylsiloxane is frequently used (nontoxic, easy to handle and commercially available). However, a Young’s modulus of 1 kPa (ultrasoft, necessary to model, e.g., brain or glial tissues) has not been achieved so far.
P35. Benjamin Wolters
Institute of Complex Systems 7 Forschungszentrum Jülich
Understanding and controlling cellular networks: Multicellular in vitro models for heart tissue
We have developed a simple accurate method for ECM protein patterning on soft silicone substrates to generate muscle microtissues which can be analyzed regarding their physiological performance.
P36. SungEun Choi
Institute of Complex Systems 7 Forschungszentrum Jülich
Positive charged lipid bilayer formation on gold for neuronal cell culture
We show that positive charged lipid is essential for bilayer formation on gold surface. This charged surface is also useful for biomimetic neuronal cell culture environment.
P37. Anna Sieben
Institute of Complex Systems 4 Forschungszentrum Jülich
Monitoring dopaminergic signaling in the retina with genetically encoded sensor proteins
Second messengers play a major role in light adaptation processes. Two of these second
messengers are calcium (Ca2+) and cyclic adenosine monophosphate (cAMP) whose pathways are known to be closely interrelated. Dopamine (DA), which is released from dopaminergic amacrine cells upon light stimulation, was reported to influence the intracellular concentration of both messengers. The intracellular cAMP concentration ([cAMP]i) is affected in two opposed ways by DA: binding of DA to the D1 receptor family results in an increase in [cAMP]i, whereas the activation of the D2 receptor family causes a reduction in [cAMP]i. DA was also reported to cause a change in the intracellular concentration of Ca2+.
Since DA is discussed as a main modulator in light adaptation processes, a better
comprehension of the dopaminergic control of cAMP and Ca2+ homeostasis is mandatory.
P38. Tobias Braun
Institute of Complex Systems 7 Forschungszentrum Jülich A novel fusogenic drug delivery system
Liposomes based on neutral and cationic lipids combined with aromatic compounds are introduced as novel drug delivery systems. Such liposomes fuse highly efficiently with the cellular plasma membrane enabling the delivery of hydrophobic and amphipathic substances into the cellular plasma membrane.
P39. Marianne Schulte
Institute of Complex Systems 6 Forschungszentrum Jülich
The antimicrobial peptide [KIGAKI]3 perturbs lipid membranes
The [KIGAKI]3 peptide is a designer antimicrobial peptide known to form amphiphilic β strands on membrane surfaces. MDsimulations were carried out to investigate the interactions between the peptide and different lipid bilayers at atomistic detail. Three 200 ns simulations