Both V, Zachar J, Zelinka J
Gen Physiol Biophys. 1983 Aug;2(4):269-78.
Some features of the interaction of guanyloribonuclease Sa from Streptomyces aureofaciens with its competitive inhibitor Guo-3'-P were investigated by 1H and 31P NMR spectroscopy. The pH dependence of chemical shifts of C(2)-H protons of the histidine residue of the enzyme were analysed, in the absence and presence of Guo-3'-P. This analysis showed that only one of the two histidines of ribonuclease Sa is located in the active site of the enzyme. 31P NMR resonances of the nucleotide and of its complex with the enzyme indicated that this histidine interacts with the phosphate group of the substrate. The possible relationship between the observed perturbation of the NMR titration curve of the active site of histidine and a conformational change in the enzyme molecule at a pH of approximately 7.5 is also discussed.
利用1H和31P核磁共振光谱研究了来自金色链霉菌的鸟苷核糖核酸酶Sa与其竞争性抑制剂郭-3'-磷酸（Guo-3'-P）相互作用的一些特征。在不存在和存在郭-3'-P的情况下，分析了该酶组氨酸残基C(2)-H质子化学位移的pH依赖性。该分析表明，核糖核酸酶Sa的两个组氨酸中只有一个位于酶的活性位点。核苷酸及其与酶复合物的31P核磁共振共振表明，该组氨酸与底物的磷酸基团相互作用。还讨论了在pH约为7.5时观察到的组氨酸活性位点核磁共振滴定曲线的扰动与酶分子构象变化之间的可能关系。
