Biosynthesis of Streptolidine Involved Two Unexpected Intermediates Produced by a Dihydroxylase and a Cyclase through Unusual Mechanisms
作者:Chin-Yuan Chang、Syue-Yi Lyu、Yu-Chen Liu、Ning-Shian Hsu、Chih-Chung Wu、Cheng-Fong Tang、Kuan-Hung Lin、Jin-Yuan Ho、Chang-Jer Wu、Ming-Daw Tsai、Tsung-Lin Li
DOI:10.1002/anie.201307989
日期:2014.2.10
sequenced from a Streptomyces variant BCRC 12163, wherein two gene products OrfP and OrfR were characterized in vitro to be a dihydroxylase and a cyclase, respectively. Thirteen high‐resolution crystal structures for both enzymes in different reaction intermediate states were snapshotted to help elucidate their catalytic mechanisms. OrfP catalyzes an FeII‐dependent double hydroxylation reaction converting
链霉菌素F(STT-F)是一种发现较早的抗生素,它由三部分组成:β-赖氨酸均聚物,氨基糖D-古洛糖胺和不常见的双环链霉菌素。链霉素的生物合成是一个长期但尚未解决的难题。在这里,遗传/生物化学/结构方法的组合被用来解决这个问题。首先从链霉菌变种BCRC 12163测序STT基因簇,其中两个基因产物OrfP和OrfR的体外特征分别是二羟化酶和环化酶。快照了两种酶在不同反应中间状态下的13种高分辨率晶体结构,以帮助阐明它们的催化机理。OrfP催化Fe II依赖性双羟基化反应转化大号-Arg入式(3 - [R,4 - [R )- (OH)2 -大号-Arg经由(3小号)-OH-大号-Arg,而OrfR催化一个不寻常的PLP依赖性消除/加成反应将(3 R,4 R)-(OH)2 - L -Arg环化为六元(4 R)-OH-环己酰胺。最终,通过进食实验将后者产品整合到STT-F中,终于揭开了生物合成之谜。