1l4k | pdb_00001l4k

Crystal Structure of CobT complexed with 3,4-dimethylaniline and nicotinate mononucleotide

spinqualitylabelsall models 1l4k, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1l4k is a 1 chain structure with sequence from Salmonella enterica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: 34A, NCN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function COBT_SALTY Catalyzes the synthesis of alpha-ribazole-5'-phosphate from nicotinate mononucleotide (NAMN) and 5,6-dimethylbenzimidazole (DMB). 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 Nicotinate mononucleotide (NaMN):5,6-dimethylbenzimidazole (DMB) phosphoribosyltransferase (CobT) from Salmonella enterica plays a central role in the synthesis of alpha-ribazole-5'-phosphate, an intermediate for the lower ligand of cobalamin. In earlier studies it proved difficult to obtain the structure of CobT bound to NaMN because it is hydrolyzed in the crystal lattice in the absence of the second substrate DMB. In an effort to map the reaction pathway of this enzyme, NaMN was captured in the active site with the substrate analogs 4,5-dimethyl-1,2-phenylenediamine, 4-methylcatechol, indole, 3,4-dimethylaniline, 2,5-dimethylaniline, 3,4-dimethylphenol, and 2-amino-p-cresol. Structures of these complexes reveal that they exclude water molecules responsible for the hydrolysis from the active site. These structures, together with the early complexes with alpha-ribazole-5'-phosphate and DMB, provide a complete description of the reaction pathway. They demonstrate that the nicotinate moiety and phosphate do not appear to move significantly between reactants and products but that the aromatic base and ribose moiety each move approximately 1.2 A toward each other in the transformation. This study also reveals that, like many other nucleotide binding proteins, coordination of DMB is accompanied by a disorder-order transition in a surface loop. The structure of apo-CobT is also reported. Capture of a labile substrate by expulsion of water molecules from the active site of nicotinate mononucleotide:5,6-dimethylbenzimidazole phosphoribosyltransferase (CobT) from Salmonella enterica.,Cheong CG, Escalante-Semerena JC, Rayment I J Biol Chem. 2002 Oct 25;277(43):41120-7. Epub 2002 Jul 5. PMID:12101181 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphoribosyltransferase 3D structures

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