Molecular mechanics of silk nanostructures under varied mechanical loading
Molecular mechanics of silk nanostructures under varied mechanical loading
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DOI：
10.1002/bip.21729
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发表时间：
2012-06-01
期刊：
影响因子：
2.9
通讯作者：
Buehler, Markus J.
中科院分区：
文献类型：
--
作者：
Bratzel, Graham;Buehler, Markus J.
蜘蛛拖丝是一种自组装的可调蛋白质复合纤维，在拉伸强度，延展性和韧性方面与许多工程纤维相媲美，使其成为最通用的生物相容性材料之一，最适合合成模拟。虽然实验研究表明，肽序列和分子结构的丝的刚度，韧性和破坏强度的丝有直接的影响，很少分子水平的分析丝组件的纳米结构，特别是，在基因序列的变化已经报道。在这项研究中，原子级结构的野生型，以及修改MaSp 1蛋白质从Nephila clavipes蜘蛛拖丝序列，获得使用基于复制品交换分子动力学和明确的水分子动力学的硅片方法，进行模拟纳米力学测试，使用不同的力控制加载条件，包括拉伸，拉出，剥离。作者探讨了N. clavipes MaSp 1肽序列，并确定在纳米力学加载条件下的行为上的差异，15股的单位细胞与840 - 990总残基用于代表一个交联β-片晶体节点的网络内的拖丝丝线的原纤维。所使用的特定载荷条件代表了从较大尺度的蛋白质网络连接性中衍生出来的概念，对力学行为有显著影响。我们的分析结合了拉伸、拔出和剥离测试，以将生化特征与机械行为联系起来。本研究中使用的方法可以在针对一系列应用的类丝可调材料的从头设计中找到广泛的应用。(C)2011 Wiley Periodicals，Inc. Biopolymers 97：408417，2012.
Spider dragline silk is a self-assembling tunable protein composite fiber that rivals many engineering fibers in tensile strength, extensibility, and toughness, making it one of the most versatile biocompatible materials and most inviting for synthetic mimicry. While experimental studies have shown that the peptide sequence and molecular structure of silk have a direct influence on the stiffness, toughness, and failure strength of silk, few molecular-level analyses of the nanostructure of silk assemblies, in particular, under variations of genetic sequences have been reported. In this study, atomistic-level structures of wildtype as well as modified 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 molecular dynamics, are subjected to simulated nanomechanical testing using different force-control loading conditions including stretch, pull-out, and peel. The authors have explored the effects of the poly-alanine length of the N. clavipes MaSp1 peptide sequence and identify differences in nanomechanical loading conditions on the behavior of a unit cell of 15 strands with 840 990 total residues used to represent a cross-linking beta-sheet crystal node in the network within a fibril of the dragline silk thread. The specific loading condition used, representing concepts derived from the protein network connectivity at larger scales, have a significant effect on the mechanical behavior. Our analysis incorporates stretching, pull-out, and peel testing to connect biochemical features to mechanical behavior. The method used in this study could find broad applications in de novo design of silk-like tunable materials for an array of applications. (C) 2011 Wiley Periodicals, Inc. Biopolymers 97: 408417, 2012.