Brooks Amanda E, Stricker Shane M, Joshi Sangeeta B, Kamerzell Timothy J, Middaugh C Russell, Lewis Randolph V
Department of Molecular Biology, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming 82070, USA.
Biomacromolecules. 2008 Jun;9(6):1506-10. doi: 10.1021/bm701124p. Epub 2008 May 6.
Spiders have evolved a complex system of silk producing glands. Each of the glands produces silk with strength and elasticity tailored to its biological purpose. Sequence analysis of the major ampullate silk reveals four highly conserved concatenated blocks of amino acids: (GA) n , A n , GPGXX, and GGX. While the GPGXX motif, which has been hypothesized to be responsible for the extensibility of the fiber, displays natural variation in its precise sequence arrangement and content, correlating these differences with particular fiber properties has been difficult. Three genetic constructs based on the Argiope aurantia sequence were engineered to progressively increase the number of GPGXX repeats in a head-to-tail assembly prior to interruption by another motif. Circular dichroism and Fourier transform infrared spectroscopy of synthetic spider silk spin dopes show secondary structures that correspond to an increase in the repeat number of GPGXX regions and an increase in the extensibility of synthetically spun recombinant fibers.
蜘蛛已经进化出了一个复杂的产丝腺体系统。每个腺体产生的丝都具有根据其生物学用途量身定制的强度和弹性。对主要壶腹丝的序列分析揭示了四个高度保守的串联氨基酸块：(GA)n、An、GPGXX和GGX。虽然据推测负责纤维可拉伸性的GPGXX基序在其精确的序列排列和含量上表现出自然变异，但将这些差异与特定的纤维特性联系起来一直很困难。基于金蛛序列设计了三种基因构建体，以便在被另一个基序中断之前，在头对尾组装中逐步增加GPGXX重复序列的数量。合成蜘蛛丝纺丝原液的圆二色性和傅里叶变换红外光谱显示，二级结构与GPGXX区域重复数的增加以及合成纺丝重组纤维的可拉伸性增加相对应。
