摘要
极端嗜热古菌———芝田硫化叶菌DNA结合蛋白Ssh7a和Ssh7b的编码基因 (ssh7a和ssh7b)在大肠杆菌中得到表达 ,表达量均达到细胞蛋白总量的 1 0 %～ 1 5%。重组蛋白通过一个包括热处理步骤的简单纯化程序得到纯化。重组Ssh7a和Ssh7b与松弛及负超螺旋DNA的结合与天然Ssh7蛋白无异 ,与天然Ssh7相似 ,Ssh7a在与DNA结合时能够固定负超螺旋 ,每固定一个负超螺旋约需 2 2个Ssh7a分子。这些结果表明天然Ssh7蛋白中的两个同源多肽与DNA结合时无明显差异。另外 ,Ssh7的甲基化与否似乎不影响该蛋白对DNA的亲和力及固定DNA超螺旋的能力。
The \%Sulfolobus shibatae\% Ssh7a and Ssh7b proteins have been separately overproduced in \%Escherichia coli\% and purified using a simple procedure which includes a heat treatment step. The recombinant and native Ssh7 proteins are similar in the ability to bind both negatively supercoiled and relaxed DNAs. Inaddition, the recombinant Ssh7a resembles the native Ssh7 protein in constraining negative DNA supercoils. Our data suggest that the two isoforms of Ssh7 interact with DNA in a similar fashion, and the methylation state of Ssh7 interact with DNA in a similar fashion, and the methylation state of Ssh7 does not affect DNA binding and supercoil constraining by the protein.
出处
《微生物学报》
CSCD
北大核心
2000年第4期359-364,共6页
Acta Microbiologica Sinica
基金
国家自然科学资金!资助项目 ( 3 9770 0 0 6)
