Methionine synthase: Difference between revisions
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==Function== | ==Function== | ||
MS is a B12-dependent enzyme responsible for regenerating methionine from homocysteine | MS is a B12-dependent enzyme responsible for regenerating methionine from homocysteine. MS uses vitamin B12 Cobalamin as a cofactor. The change from homocysteine to methionine is an SN2 reaction where the methyl group on N-5 from 5-me THF is donated. 5-me THF is a product of methylenetetrahydrofolate reductase [[MTHFR]] from the folate cycle. This is a complex reaction as tetrahydrofolate (THF), the product, is a poor leaving group and requires a "super nucleophile", Cob(I)alamin, to carry out the reaction<ref>DOI:10.1146/annurev.biochem.72.121801.161828</ref><ref name="Kung et al">DOI: 10.1038/nature10916</ref> as a methyl carrier. | ||
[[Image: Overall_methionine.gif]] | [[Image: Overall_methionine.gif]] | ||
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[[Image:Methionine synthase domains.gif]] | [[Image:Methionine synthase domains.gif]] | ||
The full structure of MS has yet to be | The full structure of MS has yet to be determine. | ||
Shown here is the <scene name='90/907471/Superposition/7'>theoretical prediction</scene> of the structure by the alphafold algorithm, with experimental structures of the N-terminal 2 domains as well as of the C-terminal 2 domins superposed. | Shown here is the <scene name='90/907471/Superposition/7'>theoretical prediction</scene> of the structure by the alphafold algorithm, with experimental structures of the N-terminal 2 domains as well as of the C-terminal 2 domins superposed. | ||