Brännvall M, Kirsebom L A
Department of Cell and Molecular Biology, Box 596, Biomedical Centre, Uppsala University, SE-751 24 Uppsala, Sweden.
Proc Natl Acad Sci U S A. 2001 Nov 6;98(23):12943-7. doi: 10.1073/pnas.221456598. Epub 2001 Oct 23.
Combinations of chemical and genetic approaches were used to study the function of divalent metal ions in cleavage of RNA by the ribozyme RNase P RNA. We show that different divalent metal ions have differential effects on cleavage site recognition and rescue of cleavage activity by mixing divalent metal ions that do not promote cleavage by themselves. We conclude that efficient and correct cleavage is the result of cooperativity between divalent metal ions bound at different sites in the RNase P RNA-substrate complex. Complementation of a mutant RNase P RNA phenotype as a result of divalent metal ion replacement is demonstrated also. This finding together with other data indicate that one of the metal ions involved in this cooperativity is positioned near the cleavage site. The possibility that the Mg(2+)/Ca(2+) ratio might regulate the activity of biocatalysts that depend on RNA for activity is discussed.
采用化学和遗传学方法相结合的方式来研究二价金属离子在核酶RNase P RNA切割RNA过程中的功能。我们发现，不同的二价金属离子对切割位点识别具有不同的影响，并且通过混合本身不能促进切割的二价金属离子可恢复切割活性。我们得出结论，高效且正确的切割是RNase P RNA-底物复合物中不同位点结合的二价金属离子之间协同作用的结果。同时也证明了由于二价金属离子替代导致的突变型RNase P RNA表型的互补性。这一发现与其他数据表明，参与这种协同作用的金属离子之一位于切割位点附近。本文还讨论了Mg(2+)/Ca(2+)比率可能调节依赖RNA发挥活性的生物催化剂活性的可能性。
