Kim M, Hyun Park B, Lee Y
Department of Chemistry, Korea Advanced Institute of Science and Technology, Taejon, 305-701, Korea.
Biochem Biophys Res Commun. 2000 Feb 5;268(1):118-23. doi: 10.1006/bbrc.2000.2084.
Deletion derivatives of C5 protein, the protein cofactor of Escherichia coli RNase P, were constructed as soluble MBP (maltose-binding protein) fusion proteins to assess the deletion effects on promoting RNase P catalysis and on binding to M1 RNA, the catalytic subunit of the enzyme. The C5 protein, with large terminal deletions, retained its promoting activity of RNase P catalysis under protein excess conditions in vitro. Some deletion derivatives complemented the temperature sensitive phenotype of E. coli A49 cells carrying the rnpA49 mutation. This ability also suggests that part of the C5 protein is enough to produce the catalytic activity of RNase P in vivo. Both the central conserved region, called the RNR motif, and the C-terminal region are essential for the binding of C5 protein to M1 RNA. Meanwhile, the N-terminal region contributes to promoting RNase P catalysis in ways other than binding to M1 RNA.
大肠杆菌核糖核酸酶P的蛋白辅因子C5蛋白的缺失衍生物，被构建为可溶性麦芽糖结合蛋白（MBP）融合蛋白，以评估缺失对促进核糖核酸酶P催化以及与该酶的催化亚基M1 RNA结合的影响。具有大的末端缺失的C5蛋白，在体外蛋白质过量条件下保留了其促进核糖核酸酶P催化的活性。一些缺失衍生物弥补了携带rnpA49突变的大肠杆菌A49细胞的温度敏感表型。这种能力还表明，C5蛋白的一部分足以在体内产生核糖核酸酶P的催化活性。被称为RNR基序的中央保守区域和C末端区域对于C5蛋白与M1 RNA的结合都是必不可少的。同时，N末端区域以不同于与M1 RNA结合的方式促进核糖核酸酶P的催化。
