摘要
结核杆菌小分子热休克蛋白Ｈｓｐ１６．３为一由三个三聚体组成的寡聚蛋白，并具有分子伴娘活性（Ｃｈａｎｇｅｔａｌ．，Ｊ．Ｂｉｏｌ．Ｃｈｅｍ．，１９９６，２７１：７２１８～７２２３）。为研究高度保守疏水片段中高度保守疏水亮氨酸残基（Ｌｅｕ１２１）对寡聚体结构和活性的影响，该残基被分别定点突变成天冬氨酸（Ａｓｐ）、天冬酰胺（Ａｓｎ）、缬氨酸（Ｖａｌ）和丙氨酸（Ａｌａ）等。结果发现当Ｌｅｕ１２１被突变成Ｖａｌ和Ａｌａ时，通过ＳＤＳ－ＰＡＧＥ凝胶电泳检测仍可见重组蛋白在大肠杆菌中的高水平表达，而当被突变成Ａｓｐ和Ａｓｎ时，在ＳＤＳ－ＰＡＧＥ胶上，见不到Ｈｓｐ１６．３蛋白带。表明该残基可能对寡聚蛋白的结构稳定起重要作用。
The Mycobacterium tuberculosis small heat shock protein Hsp16.3 functions as a molecular chaperone and was proposed to have a trimer of trimer structure (Chang et al., J. Biol. Chem., 1996, 271: 7218￣7223). To understand its role on the structure and activity of the protein, the highly conserved Leu 121 residue in Hsp16.3 was replaced by Aspartate, Asparagine, Valine, or Alanine respectively. The analysis with SDS PAGE indicated that when Leu 121 was replaced by either Valine or Alanine, high level expression of the mutant protein was observed in E.coli cells. However, when Leu 121 was replaced by either Aspartate or Asparagine, no significant amount of the corresponding Hsp16.3 mutant protein was observed. These results indicate that the Leu 121 residue plays an important role in stabilizing the Hsp16.3 protein structure.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
1999年第6期42-45,共4页
Journal of Tsinghua University(Science and Technology)
基金
国家自然科学基金
国家杰出青年科学基金
关键词
热休克蛋白
定点突变
疏水残基
保守性
Mycobacterium tuberculosis
small heat shock protein
site directed mutagenesis
