关键词: 蜘蛛丝蛋白 基因合成 串联体 蛋白质表达 大肠杆菌

Abstract:

Spider silks, being a class of nature protein fibers with many functional properties, have large potentials in the fields of biomedical, material and military applications, which are however to be sufficiently obtained through the only pathway of genetic engineering. In this study, an artificial spider silk-protein gene, SPS of the full length of 429bp, was optimally designed and synthesized on the basis of the previously reported amino acid sequences of several spider silk proteins, in which the features of structural modules and their functional correlations were particularly concerned. This synthetic gene was sub-cloned in plasmid pET-32a to generate the expression vector pET-SPS1 which was further used as the backbone for creation of a set of expression vectors, pET-SPS （2 ~ 8 ） having different muhimers of SPS gene. Finally, all SPS vectors were expressed in E. coli strain BL21 （DE3） by IIPTG induction, and the recombinant SPS fusion proteins were purified. From our results, the synthetic spider silk protein gene SPS was verified identical to the design. All SPS fusion proteins expressed in E. coli are almost fully soluble. The vectors with I - 3 multimers of SPS could be efficiently expressed, while those of more increased multimers could only give rise to poor expression. A possible interpretation for this scenario was proposed.

Key words: spider silk protein , gene synthesis , multimer , protein expression , Escherichia coli