Tsuchihashi Z, Khosla M, Herschlag D
Howard Hughes Medical Institute, Stanford University, CA 94305.
Science. 1993 Oct 1;262(5130):99-102. doi: 10.1126/science.7692597.
When the recognition sequence of a ribozyme is extended beyond a certain length, turnover is slowed and specificity is decreased. Here, it is shown that a protein can help a ribozyme overcome these general limitations on ribozyme activity. Cleavage of an RNA oligonucleotide by a hammerhead ribozyme is enhanced 10- to 20-fold upon addition of a protein derived from the p7 nucleocapsid (NC) protein of human immunodeficiency virus-type 1. The NC protein also enhances the ability of the ribozyme to discriminate between cleavage of RNA oligonucleotides with differing sequences. These catalytic improvements can be attributed to the strand exchange activity of this RNA binding protein. It is conceivable that endogenous or added proteins may provide analogous increases in ribozyme activity and specificity in vivo.
当核酶的识别序列延长至超过一定长度时，周转速度会减慢，特异性也会降低。在此研究中，结果表明一种蛋白质可帮助核酶克服这些对核酶活性的普遍限制。在添加源自人类免疫缺陷病毒1型p7核衣壳（NC）蛋白的一种蛋白质后，锤头状核酶对RNA寡核苷酸的切割增强了10至20倍。NC蛋白还增强了核酶区分不同序列RNA寡核苷酸切割的能力。这些催化活性的提高可归因于这种RNA结合蛋白的链交换活性。可以想象，内源性或添加的蛋白质可能在体内对核酶活性和特异性起到类似的增强作用。
