How is a co-methyl intermediate formed in the reaction of cobalamin-dependent methionine synthase? Theoretical evidence for a two-step methyl cation transfer mechanism.
作者： Shi-Lu Chen , Margareta R. A. Blomberg , Per E. M. Siegbahn
DOI: 10.1021/JP105729E
关键词:
摘要: A methyl-Co(cobalamin) species has been characterized to be a crucial intermediate in the last step of de novo biosynthesis methionine catalyzed by cobalamin-dependent synthase (MetH). However, exactly how it is formed still an open question. In present article, formation MetH investigated with B3LYP* hybrid DFT including van der Waals (vdW) interactions (i.e., dispersion) and using chemical model built on X-ray crystal structures. The methyl cation radical transfer mechanisms have examined various protonation states. calculations reveal that CH3−Co(III)(cobalamin) proceeds along stepwise pathway, where first from protonated methyltetrahydrofolate (CH3−THF) substrate Co(I)cobalamin. second binding His759 other side (α-face) Co. former computed rate-limiting barrier 18...
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