重组类丝状蛋白在大肠杆菌中的表达及其溶液态结构分析

Synthesis and Solution-state Structure of Silk-like Proteins Expressed in Escherichia coli

利用基因重组技术表达了具有[(GVPGV)2GG(GAGAGS)3AS]n一级结构的类丝状蛋白质(BcEn),该蛋白是把源于弹性蛋白的氨基酸序列GVPGV插入到蚕丝蛋白的结晶序列GAGAGS中,以期利用该弹性片段来调控类丝状蛋白质材料高级结构的形成以及结晶程度,从而达到控制材料性能的目的。利用园二色CD光谱对BcEn在溶液状态下的结构进行了初步分析,结果显示在对BcEn具有良好溶解性的氟有机物水合六氟丙酮中,其结构的形成依赖于BcEn分子量的大小,分子量越大越易形成比较稳定的α-螺旋结构。

Silk-like proteins, [ （GVPGV）2GG（GAGAGS）3AS]n, which consisted of the amino acid sequences selected from the repetitive crystalline region of Bombyx moil silk fibroin and animal elastin, were designed and expressed in Escherichi coil system. The insertion of elastic motif unable to form β-sheet was to impart the crystallinity and the high-order structure formation in the silk-like proteins, and even to impart the properties of materials. The CD data suggested that the structure of the proteins in hexafluoroacetone hydrate （HFA hydrate）, a good solvent to the silk materials, was length-dependent, i. e., a higher molecular weight leads to a higher ordered co-helical structure.