Cyclization mechanism catalyzed by an ATP‐grasp enzyme essential for d‐cycloserine biosynthesis
作者:Yasuyuki Matoba、Narutoshi Uda、Mako Kudo、Masanori Sugiyama
DOI:10.1111/febs.15163
日期:2020.7
generate d ‐CS, which is accompanied by the cleavage of a bond in the urea moiety of d ‐OUS to remove a carbamoyl group. Although the general ATP‐grasp enzymes catalyze an ATP‐dependent ligation reaction between two substrates, DcsG catalyzes specifically the generation of an intramolecular covalent bond. In the present study, cyanate was found in the reaction mixture, suggesting that carbamoyl group
在生物合成途径的抗结核抗生素d -cycloserine(d -CS),ö -ureido- d -丝氨酸(d -OUS)转换为d -CS。先前我们已经证明,DcsG被归类为ATP-抓握超家族酶,催化环形成以生成d- CS,并伴随着d尿素部分键的断裂。-OUS可去除氨基甲酰基。尽管一般的ATP抓握酶催化两个底物之间的ATP依赖性连接反应,但DcsG特异性催化分子内共价键的生成。在本研究中,在反应混合物中发现了氰酸酯,这表明氨基甲酰基在反应过程中作为异氰酸被消除。通过DcsG的晶体学和突变研究,我们预计了d -OUS结合所必需的残基。磷酸酯中间体必须以折叠构象结合在DcsG的狭窄口袋上,从而诱导键裂解和新的键形成,分别生成氰酸酯和d- CS。