Conformational switching and flexibility in cobalamin-dependent methionine synthase studied by small-angle X-ray scattering and cryo-electron microscopy.

ABSTRACT: Cobalamin-dependent methionine synthase (MetH) catalyzes the synthesis of methionine from homocysteine and 5-methyltetrahydrofolate (CH ₃ -H ₄ folate) using the unique chemistry of its cofactor. In doing so, MetH links the cycling of S -adenosylmethionine with the folate cycle in one-carbon metabolism. Extensive biochemical and structural studies on Escherichia coli MetH have shown that this flexible, multi-domain enzyme adopts two major conformations to prevent a futile cycle of methionine production and consumption. However, as MetH is highly dynamic as well as both a photosensitive and oxygen-sensitive metalloenzyme, it poses special challenges for structural studies, and existing structures have necessarily come from a "divide and conquer" approach.

SUBMITTER: Watkins MB 

PROVIDER: S-EPMC9934640 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature