大肠杆菌冷休克蛋白CspC的分离纯化及部分性质测定

经Sepharose Q Fast Flow阴离子交换层析和Superdex 30凝胶过滤层析,从大肠杆菌（Escherichia coli）细胞内分离纯化了一种小分子蛋白质，SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)纯度鉴定为单一条带，经质谱分析、N端测序、同源序列比较，确定该蛋白质为大肠杆菌冷休克蛋白CspC.在此基础上，用圆二色光谱测定了其二级结构含量，初步探索了其热稳定性及与单链DNA结合后的构象变化.

Purification and Partial Characterization of The Cold Shock Protein CspC from Escherichia coli

After two-step chromatography of Sepharose Q Fast Flow and Superdex 30, a small protein with molecular size of 7.2 ku was purified from Escherichia coli. The purity examined by SDS-PAGE showed as a single band. Its molecular mass measured by mass spectrum and the amino acid sequence of N terminal were in consistence with CspC, one of the cold shock proteins, in E.coli. Subsequently, the content of its secondary structure was estimated from the circular dichroism spectra, and moreover, its stability in high temperature and the conformational change after binding with single strand DNA were monitored with a CD spectrophometer.