Molecular Basis of C-N Bond Cleavage by the Glycyl Radical Enzyme Choline Trimethylamine-Lyase.
Molecular Basis of C-N Bond Cleavage by the Glycyl Radical Enzyme Choline Trimethylamine-Lyase.
复制标题
DOI：
10.1016/j.chembiol.2016.07.020
复制
发表时间：
2016-10-20
影响因子：
8.6
通讯作者：
Drennan CL
中科院分区：
文献类型：
--
作者：
Bodea S;Funk MA;Balskus EP;Drennan CL
由甘氨酰自由基酶胆碱三甲基胺裂解酶（CutC）催化的胆碱的脱氨基已经成为生产三甲胺的重要途径，三甲胺是与人类疾病和生物甲烷产生相关的微生物代谢物。在这里，我们已经确定了五个高分辨率的X-射线结构的野生型CutC和机械信息的突变体在胆碱的存在下。在一个意想不到的极性活性位点，CutC取向胆碱通过氢键与一个假定的一般碱，并通过密切的相互作用之间的酚和羧酸氧原子的蛋白质支架和极化的甲基基团的三甲基铵部分。这些结构数据，沿着活性位点突变体的生化分析，支持涉及直接消除三甲胺的机制。这项工作拓宽了我们对基于自由基的酶催化的理解，并将有助于合理设计细菌三甲胺产生的抑制剂。
Deamination of choline catalyzed by the glycyl radical enzyme choline trimethylamine-lyase (CutC) has emerged as an important route for the production of trimethylamine, a microbial metabolite associated with both human disease and biological methane production. Here, we have determined five high-resolution X-ray structures of wild-type CutC and mechanistically informative mutants in the presence of choline. Within an unexpectedly polar active site, CutC orients choline through hydrogen bonding with a putative general base, and through close interactions between phenolic and carboxylate oxygen atoms of the protein scaffold and the polarized methyl groups of the trimethylammonium moiety. These structural data, along with biochemical analysis of active site mutants, support a mechanism that involves direct elimination of trimethylamine. This work broadens our understanding of radical-based enzyme catalysis and will aid in the rational design of inhibitors of bacterial trimethylamine production.