1cb7

GLUTAMATE MUTASE FROM CLOSTRIDIUM COCHLEARIUM RECONSTITUTED WITH METHYL-COBALAMIN

spinqualitylabelsall models 1cb7, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1cb7 is a 4 chain structure with sequence from Clostridium cochlearium. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: COB, TAR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GMSS_CLOCO Catalyzes the carbon skeleton rearrangement of L-glutamate to L-threo-3-methylaspartate ((2S,3S)-3-methylaspartate).[HAMAP-Rule:MF_00526] 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 BACKGROUND: Glutamate mutase (Glm) equilibrates (S)-glutamate with (2S,3S)-3-methylaspartate. Catalysis proceeds with the homolytic cleavage of the organometallic bond of the cofactor to yield a 5'-desoxyadenosyl radical. This radical then abstracts a hydrogen atom from the protein-bound substrate to initiate the rearrangement reaction. Glm from Clostridium cochlearium is a heterotetrameric molecule consisting of two sigma and two epsilon polypeptide chains. RESULTS: We have determined the crystal structures of inactive recombinant Glm reconstituted with either cyanocobalamin or methylcobalamin. The molecule shows close similarity to the structure of methylmalonyl CoA mutase (MCM), despite poor sequence similarity between its catalytic epsilon subunit and the corresponding TIM-barrel domain of MCM. Each of the two independent B12 cofactor molecules is associated with a substrate-binding site, which was found to be occupied by a (2S,3S)-tartrate ion. A 1:1 mixture of cofactors with cobalt in oxidation states II and III was observed in both crystal structures of inactive Glm. CONCLUSIONS: The long axial cobalt-nitrogen bond first observed in the structure of MCM appears to result from a contribution of the species without upper ligand. The tight binding of the tartrate ion conforms to the requirements of tight control of the reactive intermediates and suggests how the enzyme might use the substrate-binding energy to initiate cleavage of the cobalt-carbon bond. The cofactor does not appear to have a participating role during the radical rearrangement reaction. Glutamate mutase from Clostridium cochlearium: the structure of a coenzyme B12-dependent enzyme provides new mechanistic insights.,Reitzer R, Gruber K, Jogl G, Wagner UG, Bothe H, Buckel W, Kratky C Structure. 1999 Aug 15;7(8):891-902. PMID:10467146 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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