Why is silk a tough fibre? Structure analysis of silk proteins elastomericity by small angle x-ray and neutron scattering

蚕丝的韧性和机械可调性不仅取决于可控的加工过程，还取决于蚕丝的弹性前体蛋白的自组织。水的水合作用对丝蛋白的自组织和稳定性起着重要的作用。我们实验室最近的发现表明，溶液中丝蛋白的弹性体性质可以从它们的结构紊乱和甘氨酸残基的相对含量的测量中得出。为了阐明结构紊乱和水合作用促进丝绸弹性的机制，我们建议使用小角散射（中子和x射线）、极化光谱（FTIR/CD）和热分析（DMA）来可视化这些过程。这将使我们能够通过实验和体外分析(i)丝蛋白如何在溶液中折叠和组装；（二）水化作用对丝纤维力学性能的影响。该项目将为理解和量化大型结构蛋白与其环境之间相互作用的动力学提供基础，并应用于生物聚合物纤维的人工纺丝和生物聚集体（如淀粉样蛋白）的化学控制。

Silks toughness and mechanical tunability does not depend solely on controlled processing but also on the self-organisation of the elastomeric precursor proteins of the silk. It appears that water hydration plays a major role for self-organisation and stability of silk proteins. Recent findings from our lab suggest that the elastomeric nature of silk protein in solution can be derived from a measure of their structural disorder and their relative content of glycine residues. In order to elucidate the mechanisms by which structural disorder and hydration are linked to promote elastomericity in silks we propose to visualise the processes as they occur using small angle scattering (Neutron and X-ray), polarised spectroscopy (FTIR/CD) and thermal analysis (DMA). This will allow us to examine experimentally and analyse in vitro (i) how silk proteins fold and assemble in solution; and, (ii) how hydration affects silk fibres mechanical performances. This project will provide the fundamentals to understand and quantify the dynamics of interactions between large structural proteins and their environment with application to artificial spinning of biopolymer fibres, and chemical control of biological aggregates, such as amyloids.