Fudge Douglas S, Gosline John M
Department of Zoology, University of British Columbia, Vancouver, Canada.
Proc Biol Sci. 2004 Feb 7;271(1536):291-9. doi: 10.1098/rspb.2003.2591.
We performed mechanical tests on a matrix-free keratin model-hagfish slime threads-to test the hypothesis that intermediate filaments (IFs) in hydrated hard alpha-keratins are maintained in a partly dehydrated state. This hypothesis predicts that dry IFs should possess mechanical properties similar to the properties of hydrated hard alpha-keratins, and should swell more than hard alpha-keratins in water. Mechanical and swelling measurements of hagfish threads were consistent with both of these predictions, suggesting that an elastomeric keratin matrix resists IF swelling and keeps IF stiffness and yield stress high. The elastomeric nature of the matrix is indirectly supported by the inability of matrix-free IFs (i.e. slime threads) to recover from post-yield deformation. We propose a general conceptual model of the structural mechanics of IF-based materials that predicts the effects of hydration and cross-linking on stiffness, yield stress and extensibility.
我们对一种无基质角蛋白模型——盲鳗黏液丝进行了力学测试，以验证水合硬α-角蛋白中的中间丝（IFs）保持在部分脱水状态这一假设。该假设预测，干燥的IFs应具有与水合硬α-角蛋白相似的力学性能，并且在水中的膨胀程度应超过硬α-角蛋白。盲鳗丝的力学和膨胀测量结果与这两个预测均相符，这表明弹性角蛋白基质可抵抗IFs的膨胀，并保持IFs的高刚度和屈服应力。无基质IFs（即黏液丝）无法从屈服后变形中恢复，这间接支持了基质的弹性性质。我们提出了一种基于IFs材料的结构力学通用概念模型，该模型预测了水合作用和交联对刚度、屈服应力和延展性的影响。
