Transition State Structure of <i>E. coli t</i>RNA-Specific Adenosine Deaminase
作者:Minkui Luo、Vern L. Schramm
DOI:10.1021/ja078008x
日期:2008.2.1
rotation occur on the path to the transition state. The late SNAr transition-state established here for E. coli TadA is similar to the late transition state reported for cytidine deaminase. It differs from the early SNAr transition states described recently for the adenosine deaminases from human, bovine, and Plasmodium falciparum sources. The ecTadA transition state structure reveals the detailed architecture
细菌 tRNA 特异性腺苷脱氨酶 (TadA) 在 tRNA 的摆动位置催化腺苷基本脱氨为肌苷,并且是允许单个 tRNA 物种识别多个密码子所必需的。大肠杆菌 TadA 的过渡态结构通过动力学同位素效应 (KIE) 和量子化学计算进行表征。大肠杆菌 tRNA(Arg2) 的茎环用作最小化的 TadA 底物,其腺苷酸编辑位点同位素标记为 [1'-(3)H]、[5'-(3)H2]、[1 '-(14)C], [6-(13)C], [6-(15)N], [6-(13)C, 6-(15)N] 和 [1-(15)N] . [6-(13)C]-, [6-(15)N]-, [1-(15)N]-, [1'- 的本征 KIE 分别为 1.014、1.022、0.994、1.014 和 0.963 (3)H]-、[5'-(3)H2]-分别标记的底物。KIE 套件与具有完整的亲 S 面羟基攻击和几乎完整的 N1 质子化的晚期