2obc

The crystal structure of RibD from Escherichia coli in complex with a substrate analogue, ribose 5-phosphate (beta form), bound to the active site of the reductase domain

spinqualitylabelsall models 2obc, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2obc is a 2 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3Å Ligands: MSE, RP5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RIBD_ECOLI Converts 2,5-diamino-6-(ribosylamino)-4(3h)-pyrimidinone 5'-phosphate into 5-amino-6-(ribosylamino)-2,4(1h,3h)-pyrimidinedione 5'-phosphate. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed We have determined the crystal structure of the bi-functional deaminase/reductase enzyme from Escherichia coli (EcRibD) that catalyzes two consecutive reactions during riboflavin biosynthesis. The polypeptide chain of EcRibD is folded into two domains where the 3D structure of the N-terminal domain (1-145) is similar to cytosine deaminase and the C-terminal domain (146-367) is similar to dihydrofolate reductase. We showed that EcRibD is dimeric and compared our structure to tetrameric RibG, an ortholog from Bacillus subtilis (BsRibG). We have also determined the structure of EcRibD in two binary complexes with the oxidized cofactor (NADP(+)) and with the substrate analogue ribose-5-phosphate (RP5) and superposed these two in order to mimic the ternary complex. Based on this superposition we propose that the invariant Asp200 initiates the reductive reaction by abstracting a proton from the bound substrate and that the pro-R proton from C4 of the cofactor is transferred to C1 of the substrate. A highly flexible loop is found in the reductase active site (159-173) that appears to control cofactor and substrate binding to the reductase active site and was therefore compared to the corresponding Met20 loop of E. coli dihydrofolate reductase (EcDHFR). Lys152, identified by comparing substrate analogue (RP5) coordination in the reductase active site of EcRibD with the homologous reductase from Methanocaldococcus jannaschii (MjaRED), is invariant among bacterial RibD enzymes and could contribute to the various pathways taken during riboflavin biosynthesis in bacteria and yeast. The crystal structure of the bifunctional deaminase/reductase RibD of the riboflavin biosynthetic pathway in Escherichia coli: implications for the reductive mechanism.,Stenmark P, Moche M, Gurmu D, Nordlund P J Mol Biol. 2007 Oct 12;373(1):48-64. Epub 2006 Dec 8. PMID:17765262 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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