Publications

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11 Publications visible to you, out of a total of 11

Abstract (Expand)

Hydrodynamic flow in the spider duct induces conformational changes in dragline spider silk proteins (spidroins) and drives their assembly, but the underlying physical mechanisms are still elusive. Here we address this challenging multiscale problem with a complementary strategy of atomistic and coarse-grained molecular dynamics simulations with uniform flow. The conformational changes at the molecular level were analyzed for single-tethered spider silk peptides. Uniform flow leads to coiled-to-stretch transitions and pushes alanine residues into β sheet and poly-proline II conformations. Coarse-grained simulations of the assembly process of multiple semi-flexible block copolymers using multi-particle collision dynamics reveal that the spidroins aggregate faster but into low-order assemblies when they are less extended. At medium-to-large peptide extensions (50%–80%), assembly slows down and becomes reversible with frequent association and dissociation events, whereas spidroin alignment increases and alanine repeats form ordered regions. Our work highlights the role of flow in guiding silk self-assembly into tough fibers by enhancing alignment and kinetic reversibility, a mechanism likely relevant also for other proteins whose function depends on hydrodynamic flow.

Authors: Ana M. Herrera-Rodríguez, Anil Kumar Dasanna, Csaba Daday, Eduardo R. Cruz-Chú, Camilo Aponte-Santamaría, Ulrich S. Schwarz, Frauke Gräter

Date Published: 5th Oct 2023

Publication Type: Journal

Abstract (Expand)

Cellular mechanosensing is pivotal for virtually all biological processes, and many molecular mechano-sensors and their way of function are being uncovered. In this work, we suggest that c-Src kinase acts as a direct mechano-sensor. c-Src is responsible for, among others, cell proliferation, and shows increased activity in stretched cells. In its native state, c-Src has little basal activity, because its kinase domain binds to an SH2 and SH3 domain. However, it is known that c-Src can bind to p130Cas, through which force can be transmitted to the membrane. Using molecular dynamics simulations, we show that force acting between the membrane-bound N-terminus of the SH3 domain and p130Cas induces partial SH3 unfolding, thereby impeding rebinding of the kinase domain onto SH2/SH3 and effectively enhancing kinase activity. Forces involved in this process are slightly lower or similar to the forces required to pull out c-Src from the membrane through the myristoyl linker, and key interactions involved in this anchoring are salt bridges between negative lipids and nearby basic residues in c-Src. Thus, c-Src appears to be a candidate for an intriguing mechanosensing mechanism of impaired kinase inhibition, which can be potentially tuned by membrane composition and other environmental factors.

Authors: Csaba Daday, Svenja de Buhr, Davide Mercadante, Frauke Gräter

Date Published: 2nd Feb 2022

Publication Type: Journal

Abstract (Expand)

Single-molecule force spectroscopy and classical molecular dynamics are natural allies. Recent advances in both experiments and simulations have increasingly facilitated a direct comparison of SMFS and MD data, most importantly by closing the gap between time scales, which has been traditionally at least 5 orders of magnitudes wide. In this review, we will explore these advances chiefly on the computational side. We focus on protein dynamics under force and highlight recent studies that showcase how lower loading rates and more statistics help to better interpret previous experiments and to also motivate new ones. At the same time, steadily increasing system sizes are used to mimic more closely the mechanical environment in the biological context. We showcase some of these advances on atomistic and coarse-grained scale, from asymmetric membrane tension to larger (multidomain/multimeric) protein assemblies under force.

Authors: Florian Franz, Csaba Daday, Frauke Gräter

Date Published: 1st Apr 2020

Publication Type: Journal

Abstract

Not specified

Authors: Shashi Kumar Suman, Csaba Daday, Teresa Ferraro, Thanh Vuong-Brender, Saurabh Tak, Sophie Quintin, François Robin, Frauke Gräter, Michel Labouesse

Date Published: 13th Dec 2019

Publication Type: Journal

Abstract

Not specified

Authors: Steven Sheridan, Frauke Gräter, Csaba Daday

Date Published: 19th Apr 2019

Publication Type: Journal

Abstract

Not specified

Authors: Magnus Sebastian Bauer, Fabian Baumann, Csaba Daday, Pilar Redondo, Ellis Durner, Markus Andreas Jobst, Lukas Frederik Milles, Davide Mercadante, Diana Angela Pippig, Hermann Eduard Gaub, Frauke Gräter, Daniel Lietha

Date Published: 2nd Apr 2019

Publication Type: Journal

Abstract (Expand)

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial heart disease linked to mutations in several desmosomal proteins, but the specific effects of these mutations on the molecular level are poorly understood. Among the many documented ARVC-related genetic variants, a striking hotspot of nine mutations has been identified in the plakin domain of desmoplakin. This hotspot can be found at the meeting point of three different subdomains of desmoplakin: two spectrin repeats and a Src homology 3 domain. We set out to understand the effect of these mutations. We determine, using molecular dynamics simulations, how these mutations affect the mechanics of this interface, performing two different classes of simulations. First, we sample the dynamics of the plakin domain, in particular the tendency of the interdomain hinge to buckle, and then we apply an external force onto the constructs and determine the force necessary to break them. We find that surface-exposed mutations are not affecting the dynamics to a very large degree but that most buried mutations make the junction more flexible and decrease the rupture forces observed. Our data suggest that buried ARVC mutations destabilize desmoplakin and thereby impair desmosome integrity under tension.

Authors: Csaba Daday, Laura Marlene Mateyka, Frauke Gräter

Date Published: 1st Mar 2019

Publication Type: Journal

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