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Viscoelastic relaxation time and structural evolution during length contraction of spider silk protein nanostructures

Published online by Cambridge University Press:  10 September 2013

Graham Bratzel
Affiliation:
Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue Room 1-235A&B, Cambridge, Massachusetts; Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts
Zhao Qin
Affiliation:
Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue Room 1-235A&B, Cambridge, Massachusetts
Markus J. Buehler*
Affiliation:
Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue Room 1-235A&B, Cambridge, Massachusetts
*
Address all correspondence to Markus J. Buehler at mbuehler@mit.edu
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Abstract

Spider dragline silk is a self-assembling protein that rivals many engineering fibers in strength, extensibility, and toughness, making it a versatile biocompatible material. Here, atomistic-level structures of wildtype MaSp1 protein from the Nephila clavipes spider dragline silk sequences, obtained using an in silico approach based on replica exchange molecular dynamics and explicit water, are subjected to nanomechanical testing and released preceding failure. We approximate the relaxation time from an exponential decay function, and identify permanent changes in secondary structure. Our work provides fundamental insights into the time-dependent properties of silk and possibly other protein materials.

Type
Research Letters
Copyright
Copyright © Materials Research Society 2013 

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