1buc
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(New page: 200px<br /><applet load="1buc" size="450" color="white" frame="true" align="right" spinBox="true" caption="1buc, resolution 2.5Å" /> '''THREE-DIMENSIONAL STR...)
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Revision as of 09:48, 20 November 2007
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THREE-DIMENSIONAL STRUCTURE OF BUTYRYL-COA DEHYDROGENASE FROM MEGASPHAERA ELSDENII
Overview
The crystal structure of butyryl-CoA dehydrogenase (BCAD) from Megasphaera, elsdenii complexed with acetoacetyl-CoA has been solved at 2.5 A, resolution. The enzyme crystallizes in the P422 space group with cell, dimensions a = b = 107.76 A and c = 153.67 A. BCAD is a bacterial analog, of short chain acyl-CoA dehydrogenase from mammalian mitochondria., Mammalian acyl-CoA dehydrogenases are flavin adenine dinucleotide, (FAD)-containing enzymes that catalyze the first step in the, beta-oxidation of fatty acids. Although specific for substrate chain, lengths, they exhibit high sequence homology. The structure of BCAD was, solved by the molecular replacement method using the atomic coordinates of, pig liver medium chain acyl-CoA dehydrogenase (MCAD). The structure was, refined to an R-factor of 19.3%. The overall polypeptide fold of BCAD is, similar to that of MCAD. E367 in BCAD is at the same position and in a, similar conformation as the catalytic base in MCAD, E376. The main, enzymatic differences between BCAD and MCAD are their substrate, specificities and the significant oxygen reactivity exhibited by BCAD but, not by MCAD. The substrate binding cavity of BCAD is relatively shallow, compared to that of MCAD, as consequences of both a single amino acid, insertion and differences in the side chains of the helices that make the, binding site. The si-face of the FAD in BCAD is more exposed to solvent, than that in MCAD. Therefore solvation can stabilize the superoxide anion, and considerably increase the rate of oxidation of reduced flavin in the, bacterial enzyme.
About this Structure
1BUC is a Single protein structure of sequence from Megasphaera elsdenii with CAA and FAD as ligands. Active as Butyryl-CoA dehydrogenase, with EC number 1.3.99.2 Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of butyryl-CoA dehydrogenase from Megasphaera elsdenii., Djordjevic S, Pace CP, Stankovich MT, Kim JJ, Biochemistry. 1995 Feb 21;34(7):2163-71. PMID:7857927
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