Guerrier-Takada C, Haydock K, Allen L, Altman S
Biochemistry. 1986 Apr 8;25(7):1509-15. doi: 10.1021/bi00355a006.
M1 RNA, the RNA subunit of ribonuclease P from Escherichia coli, can under certain conditions catalytically cleave precursors to tRNA in the absence of C5, the protein moiety of RNase P. M1 RNA itself is not cleaved during the reaction, nor does it form any covalent bonds with its substrate. Only magnesium and, to a lesser extent, manganese ions can function at the catalytic center of M1 RNA. Several other ions either inhibit the binding of magnesium ion at the active site or function as structural counterions. The reaction rate of cleavage of precursors to tRNAs by M1 RNA is enhanced in the presence of poly-(ethylene glycol) or 2-methyl-2,4-pentanediol. Many aspects of the reaction catalyzed by M1 RNA are compatible with a mechanism in which phosphodiester bond cleavage is mediated by metal ion.
M1 RNA是来自大肠杆菌的核糖核酸酶P的RNA亚基，在某些条件下，它能够在没有核糖核酸酶P的蛋白质部分C5的情况下，催化切割tRNA前体。在反应过程中，M1 RNA自身不会被切割，也不会与其底物形成任何共价键。只有镁离子，以及在较小程度上的锰离子，能够在M1 RNA的催化中心发挥作用。其他几种离子要么抑制镁离子在活性位点的结合，要么作为结构抗衡离子发挥作用。在聚乙二醇或2-甲基-2,4-戊二醇存在的情况下，M1 RNA切割tRNA前体的反应速率会提高。M1 RNA催化的反应的许多方面都与一种由金属离子介导磷酸二酯键切割的机制相符。
