Pomeranz Krummel D A, Kent O, MacMillan A M, Altman S
Department of Molecular Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, 06511, USA.
J Mol Biol. 2000 Feb 4;295(5):1113-8. doi: 10.1006/jmbi.1999.3424.
To gain an understanding of structural changes induced in substrates by Escherichia coli ribonuclease P (RNase P), we have incorporated an interstrand disulfide crosslink proximal to the cleavage site in a model substrate. RNase P is able to process the reduced, non-crosslinked form of this substrate as well as a substrate in which the free thiol molecules have been alkylated with iodoacetamide. However, the oxidized, crosslinked form is cleaved at a significantly lower rate. Therefore, helical unwinding of the analog of the aminoacyl stem of the substrate near its site of cleavage may be necessary for efficient processing by E. coli RNase P.
为了了解大肠杆菌核糖核酸酶P（RNase P）在底物中诱导的结构变化，我们在模型底物的切割位点附近引入了链间二硫键交联。RNase P能够处理这种底物的还原态、非交联形式以及游离硫醇分子已用碘乙酰胺烷基化的底物。然而，氧化的交联形式的切割速率要低得多。因此，底物氨基酰茎类似物在其切割位点附近的螺旋解旋可能是大肠杆菌RNase P进行有效加工所必需的。
