FACTORS INFLUENCING GENETIC TRANSCRIPTION-INITIATION AND TERMINATION

对大肠杆菌核糖核酸酶H的晶体结构分析表明， 一个被五个阿尔法螺旋包围的五链β-折叠。保守的， 必需的羧酸氨基酸可能与镁离子结合，从而 启动酶和底物之间的相互作用。这些 带负电荷的保守氨基酸与其他保守氨基酸汇聚在一起 分子一侧的残基。逆转录病毒和酵母核糖核酸酶HI 可能影响其位置和/或功能的其他域 酵母菌的核糖核酸酶H结构域的功能没有剩余的 蛋白质而逆转录病毒RNaseH表现出对大多数 聚合酶区域的最大活性。

Analysis of the crystal structure of E. coli RNase H indicates a protein of a five-stranded beta-sheet surrounded by five alpha-helices. Conserved, essential carboxylic acid amino acids probably bind Mg++ and thereby initiate an interaction between the enzyme and the substrate. These negatively charged, conserved amino acids converge with other conserved residues on one face of the molecule. Retroviral and yeast RNase HI have additional domains which may affect the location and/or function of their RNases H. The RNase H domain of yeast functions without the remainder of the protein whereas the retroviral RNase H exhibits a requirement for most of the polymerase domain for maximal activity.