1pj5
Crystal structure of dimethylglycine oxidase of Arthrobacter globiformis in complex with acetate
OverviewOverview
Here we report crystal structures of dimethylglycine oxidase (DMGO) from the bacterium Arthrobacter globiformis, a bifunctional enzyme that catalyzes the oxidation of N,N-dimethyl glycine and the formation of 5,10-methylene tetrahydrofolate. The N-terminal region binds FAD covalently and oxidizes dimethylglycine to a labile iminium intermediate. The C-terminal region binds tetrahydrofolate, comprises three domains arranged in a ring-like structure and is related to the T-protein of the glycine cleavage system. The complex with folinic acid indicates that this enzyme selectively activates the N10 amino group for initial attack on the substrate. Dead-end reactions with oxidized folate are avoided by the strict stereochemical constraints imposed by the folate-binding funnel. The active sites in DMGO are approximately 40 A apart, connected by a large irregular internal cavity. The tetrahydrofolate-binding funnel serves as a transient entry-exit port, and access to the internal cavity is controlled kinetically by tetrahydrofolate binding. The internal cavity enables sequestration of the reactive iminium intermediate prior to reaction with tetrahydrofolate and avoids formation of toxic formaldehyde. This mode of channelling in DMGO is distinct from other channelling mechanisms.
About this StructureAbout this Structure
1PJ5 is a Single protein structure of sequence from Arthrobacter globiformis. Full crystallographic information is available from OCA.
ReferenceReference
Channelling and formation of 'active' formaldehyde in dimethylglycine oxidase., Leys D, Basran J, Scrutton NS, EMBO J. 2003 Aug 15;22(16):4038-48. PMID:12912903 Page seeded by OCA on Sat May 3 05:08:35 2008