1lt7
From Proteopedia
Oxidized Homo sapiens betaine-homocysteine S-methyltransferase in complex with four Sm(III) ions
Overview
Betaine-homocysteine methyl transferase (BHMT) catalyzes the synthesis of methionine from betaine and homocysteine (Hcy), utilizing a zinc ion to activate Hcy. BHMT is a key liver enzyme that is important for homocysteine homeostasis. X-ray structures of human BHMT in its oxidized (Zn-free) and reduced (Zn-replete) forms, the latter in complex with the bisubstrate analog, S(delta-carboxybutyl)-L-homocysteine, were determined at resolutions of 2.15 A and 2.05 A. BHMT is a (beta/alpha)(8) barrel that is distorted to construct the substrate and metal binding sites. The zinc binding sequences G-V/L-N-C and G-G-C-C are at the C termini of strands beta6 and beta8. Oxidation to the Cys217-Cys299 disulfide and expulsion of Zn are accompanied by local rearrangements. The structures identify Hcy binding fingerprints and provide a prototype for the homocysteine S-methyltransferase family.
About this Structure
1LT7 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Betaine-homocysteine methyltransferase: zinc in a distorted barrel., Evans JC, Huddler DP, Jiracek J, Castro C, Millian NS, Garrow TA, Ludwig ML, Structure. 2002 Sep;10(9):1159-71. PMID:12220488 Page seeded by OCA on Sat May 3 00:15:51 2008
