1d0s
From Proteopedia
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|PDB= 1d0s |SIZE=350|CAPTION= <scene name='initialview01'>1d0s</scene>, resolution 1.9Å | |PDB= 1d0s |SIZE=350|CAPTION= <scene name='initialview01'>1d0s</scene>, resolution 1.9Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=DMD:5,6-DIMETHYLBENZIMIDAZOLE'>DMD</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene> |
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Nicotinate-nucleotide--dimethylbenzimidazole_phosphoribosyltransferase Nicotinate-nucleotide--dimethylbenzimidazole phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.21 2.4.2.21] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Nicotinate-nucleotide--dimethylbenzimidazole_phosphoribosyltransferase Nicotinate-nucleotide--dimethylbenzimidazole phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.21 2.4.2.21] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1d0v|1D0V]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1d0s FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1d0s OCA], [http://www.ebi.ac.uk/pdbsum/1d0s PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1d0s RCSB]</span> | ||
}} | }} | ||
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[[Category: Escalante-Semerena, J C.]] | [[Category: Escalante-Semerena, J C.]] | ||
[[Category: Rayment, I.]] | [[Category: Rayment, I.]] | ||
| - | [[Category: DMD]] | ||
| - | [[Category: PO4]] | ||
[[Category: dinucleotide-binding motif]] | [[Category: dinucleotide-binding motif]] | ||
[[Category: phosphoribosyl transferase]] | [[Category: phosphoribosyl transferase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:32:12 2008'' |
Revision as of 16:32, 30 March 2008
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| , resolution 1.9Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Activity: | Nicotinate-nucleotide--dimethylbenzimidazole phosphoribosyltransferase, with EC number 2.4.2.21 | ||||||
| Related: | 1D0V
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF NICOTINATE MONONUCLEOTIDE : 5,6-DIMETHYLBENZIMIDAZOLE PHOSPHORIBOSYLTRANSFERASE (COBT) FROM SALMONELLA TYPHIMURIUM COMPLEXED WITH 5, 6-DIMETHYLBENZIMIDAZOLE
Overview
Nicotinate mononucleotide:5,6-dimethylbenzimidazole phosphoribosyltransferase (CobT) from Salmonella typhimurium plays a central role in the synthesis of alpha-ribazole, which is a key component of the lower ligand of cobalamin. Two X-ray structures of CobT are reported here at 1.9 A resolution. First, a complex of CobT with 5,6-dimethylbenzimidazole, and second, a complex of CobT with its reaction products, nicotinate and alpha-ribazole-5'-phosphate. CobT was cocrystallized with 5,6-dimethylbenzimidazole (DMB) in the space group P2(1)2(1)2 with unit cell dimensions of a = 72.1 A, b = 90.2 A, and c = 47.5 A and one protomer per asymmetric unit. Subsequently, the crystals containing DMB were soaked in nicotinate mononucleotide whereupon the physiological reaction occurred in the crystal lattice to yield nicotinate and alpha-ribazole-5'-phosphate. These studies show that CobT is a dimer where each subunit consists of two domains. The large domain is dominated by a parallel six-stranded beta-sheet with connecting alpha-helices that exhibit the topology of a Rossmann fold. The small domain is made from components of the N- and C-terminal sections of the polypeptide chain and contains a three-helix bundle. The fold of CobT is unrelated to the type I and II phosphoribosylpyrophosphate dependent transferases and does not appear to be related to any other protein whose structure is known. The enzyme active site is located in a large cavity formed by the loops at the C-terminal ends of the beta-strands and the small domain of the neighboring subunit. DMB binds in a hydrophobic pocket created in part by the neighboring small domain. This is consistent with the broad specificity of this enzyme for aromatic substrates [Trzebiatowski, J. R., Escalante-Semerena (1997) J. Biol. Chem. 272, 17662-17667]. The binding site for DMB suggests that Glu317 is the catalytic base required for the reaction. The remainder of the cavity binds the nicotinate and ribose-5'-phosphate moieties, which are nestled within the loops at the ends of the beta-strands. Interestingly, the orientation of the substrate and products are opposite from that expected for a Rossmann fold.
About this Structure
1D0S is a Single protein structure of sequence from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
The three-dimensional structures of nicotinate mononucleotide:5,6- dimethylbenzimidazole phosphoribosyltransferase (CobT) from Salmonella typhimurium complexed with 5,6-dimethybenzimidazole and its reaction products determined to 1.9 A resolution., Cheong CG, Escalante-Semerena JC, Rayment I, Biochemistry. 1999 Dec 7;38(49):16125-35. PMID:10587435
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