1x74 | pdb_00001x74

Alpha-methylacyl-CoA racemase from Mycobacterium tuberculosis- mutational and structural characterization of the fold and active site

spinqualitylabelsall models 1x74, resolution 1.79Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1x74 is a 4 chain structure with sequence from "bacillus_tuberculosis"_(zopf_1883)_klein_1884 "bacillus tuberculosis" (zopf 1883) klein 1884. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, PO4 Activity: Alpha-methylacyl-CoA racemase, with EC number 5.1.99.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum 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 Alpha-methylacyl-CoA racemase (Amacr) catalyzes the racemization of alpha-methyl-branched CoA esters. Sequence comparisons have shown that this enzyme is a member of the family III CoA transferases. The mammalian Amacr is involved in bile acid synthesis and branched-chain fatty acid degradation. In human, mutated variants of Amacr have been shown to be associated with disease states. Amino acid sequence alignment of Amacrs and its homologues from various species revealed 26 conserved protic residues, assumed to be potential candidates as catalytic residues. Amacr from Mycobacterium tuberculosis (MCR) was taken as a representative of the racemases. To determine their importance for efficient catalysis, each of these 26 protic residues of MCR was mutated into an alanine, respectively, and the mutated variants were overexpressed in Escherichia coli. It was found that four variants (R91A, H126A, D156A, and E241A) were properly folded but had much decreased catalytic efficiency. Apparently, Arg91, His126, Asp156, and Glu241 are important catalytic residues of MCR. The importance of these residues for catalysis can be rationalized by the 1.8 A resolution crystal structure of MCR, which shows that the catalytic site is at the interface between the large and small domain of two different subunits of the dimeric enzyme. This crystal structure is the first structure of a complete enzyme of the bile acid synthesis pathway. It shows that MCR has unique structural features, not seen in the structures of the sequence related formyl-CoA transferases, suggesting that the family III CoA transferases can be subdivided in at least two classes, being racemases and CoA transferases. Alpha-methylacyl-CoA racemase from Mycobacterium tuberculosis. Mutational and structural characterization of the active site and the fold.,Savolainen K, Bhaumik P, Schmitz W, Kotti TJ, Conzelmann E, Wierenga RK, Hiltunen JK J Biol Chem. 2005 Apr 1;280(13):12611-20. Epub 2005 Jan 4. PMID:15632186 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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