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1Q7Q

Cobalamin-dependent methionine synthase (1-566) from T. maritima (Oxidized, Orthorhombic)

Summary for 1Q7Q
Entry DOI10.2210/pdb1q7q/pdb
Related1Q7M 1Q7Z 1Q85 1Q8A
Descriptor5-methyltetrahydrofolate S-homocysteine methyltransferase (2 entities in total)
Functional Keywordshomocysteine, methionine, folate, cobalamin, vitamin b12, transferase
Biological sourceThermotoga maritima
Total number of polymer chains2
Total formula weight127266.30
Authors
Evans, J.C.,Huddler, D.P.,Hilgers, M.T.,Romanchuk, G.,Matthews, R.G.,Ludwig, M.L. (deposition date: 2003-08-19, release date: 2004-03-23, Last modification date: 2024-10-09)
Primary citationEvans, J.C.,Huddler, D.P.,Hilgers, M.T.,Romanchuk, G.,Matthews, R.G.,Ludwig, M.L.
Structures of the N-terminal modules imply large domain motions during catalysis by methionine synthase.
Proc.Natl.Acad.Sci.Usa, 101:3729-3736, 2004
Cited by
PubMed Abstract: B(12)-dependent methionine synthase (MetH) is a large modular enzyme that utilizes the cobalamin cofactor as a methyl donor or acceptor in three separate reactions. Each methyl transfer occurs at a different substrate-binding domain and requires a different arrangement of modules. In the catalytic cycle, the cobalamin-binding domain carries methylcobalamin to the homocysteine (Hcy) domain to form methionine and returns cob(I)alamin to the folate (Fol) domain for remethylation by methyltetrahydrofolate (CH(3)-H(4)folate). Here, we describe crystal structures of a fragment of MetH from Thermotoga maritima comprising the domains that bind Hcy and CH(3)-H(4)folate. These substrate-binding domains are (beta alpha)(8) barrels packed tightly against one another with their barrel axes perpendicular. The properties of the domain interface suggest that the two barrels remain associated during catalysis. The Hcy and CH(3)-H(4)folate substrates are bound at the C termini of their respective barrels in orientations that position them for reaction with cobalamin, but the two active sites are separated by approximately 50 A. To complete the catalytic cycle, the cobalamin-binding domain must travel back and forth between these distant active sites.
PubMed: 14752199
DOI: 10.1073/pnas.0308082100
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (3.1 Å)
Structure validation

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