Atomistic model of the spider silk nanostructure

被引:80
作者
Keten, Sinan [1 ]
Buehler, Markus J. [1 ,2 ,3 ]
机构
[1] MIT, Lab Atomist & Mol Mech, Dept Civil & Environm Engn, Cambridge, MA 02139 USA
[2] MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA
[3] MIT, Ctr Computat Engn, Cambridge, MA 02139 USA
基金
美国国家科学基金会;
关键词
biomechanics; molecular biophysics; molecular configurations; molecular dynamics method; polymers; proteins; MOLECULAR-DYNAMICS SIMULATIONS; MAJOR AMPULLATE SILK; DRAGLINE SILK; SECONDARY STRUCTURE; NEPHILA-CLAVIPES; ORIENTATION; PROTEINS; ELASTICITY; CRYSTALS; STRENGTH;
D O I
10.1063/1.3385388
中图分类号
O59 [应用物理学];
学科分类号
摘要
Spider silk is an ultrastrong and extensible self-assembling biopolymer that outperforms the mechanical characteristics of many synthetic materials including steel. Here we report atomic-level structures that represent aggregates of MaSp1 proteins from the N. Clavipes silk sequence based on a bottom-up computational approach using replica exchange molecular dynamics. We discover that poly-alanine regions predominantly form distinct and orderly beta-sheet crystal domains while disorderly structures are formed by poly-glycine repeats, resembling 3(1)-helices. These could be the molecular source of the large semicrystalline fraction observed in silks, and also form the basis of the so-called "prestretched" molecular configuration. Our structures are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content.
引用
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页数:3
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