2gag
Heteroteterameric sarcosine: structure of a diflavin metaloenzyme at 1.85 a resolution
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OverviewOverview
The crystal structure of heterotetrameric sarcosine oxidase (TSOX) from, Pseudomonas maltophilia has been determined at 1.85 A resolution. TSOX, contains three coenzymes (FAD, FMN and NAD+), four different subunits, (alpha, 103 kDa; beta, 44 kDa; gamma, 21 kDa; delta, 11 kDa) and catalyzes, the oxidation of sarcosine (N-methylglycine) to yield hydrogen peroxide, glycine and formaldehyde. In the presence of tetrahydrofolate, the, oxidation of sarcosine is coupled to the formation of, 5,10-methylenetetrahydrofolate. The NAD+ and putative folate binding sites, are located in the alpha-subunit. The FAD binding site is in the, beta-subunit. FMN is bound at the interface of the alpha and, beta-subunits. The FAD and FMN rings are separated by a short segment of, the beta-subunit with the closest atoms located 7.4 A apart. Sulfite, an, inhibitor of oxygen reduction, is bound at the FMN site. 2-Furoate, a, competitive inhibitor with respect to sarcosine, is bound at the FAD site., The sarcosine dehydrogenase and 5,10-methylenetetrahydrofolate synthase, sites are 35 A apart but connected by a large internal cavity, (approximately 10,000 A3). An unexpected zinc ion, coordinated by three, cysteine and one histidine side-chains, is bound to the delta-subunit. The, N-terminal half of the alpha subunit of TSOX (alphaA) is closely similar, to the FAD-binding domain of glutathione reductase but with NAD+ replacing, FAD. The C-terminal half of the alpha subunit of TSOX (alphaB) is similar, to the C-terminal half of dimethylglycine oxidase and the T-protein of the, glycine cleavage system, proteins that bind tetrahydrofolate. The, beta-subunit of TSOX is very similar to monomeric sarcosine oxidase. The, gamma-subunit is similar to the C-terminal sub-domain of alpha-TSOX. The, delta-subunit shows little similarity with any PDB entry. The alphaA, domain/beta-subunit sub-structure of TSOX closely resembles the alphabeta, dimer of L-proline dehydrogenase, a heteroctameric protein (alphabeta)4, that shows highest overall similarity to TSOX.
About this StructureAbout this Structure
2GAG is a Protein complex structure of sequences from Stenotrophomonas maltophilia with , , , , , and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Heterotetrameric sarcosine oxidase: structure of a diflavin metalloenzyme at 1.85 A resolution., Chen ZW, Hassan-Abdulah A, Zhao G, Jorns MS, Mathews FS, J Mol Biol. 2006 Jul 28;360(5):1000-18. Epub 2006 Jun 15. PMID:16820168
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