1leh
From Proteopedia
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LEUCINE DEHYDROGENASE FROM BACILLUS SPHAERICUS
Overview
BACKGROUND: Glutamate, phenylalanine and leucine dehydrogenases catalyze, the NAD(P)(+)-linked oxidative deamination of L-amino acids to the, corresponding 2-oxoacids, and sequence homology between these enzymes, clearly indicates the existence of an enzyme superfamily related by, divergent evolution. We have undertaken structural studies on a number of, members of this family in order to investigate the molecular basis of, their differential amino acid specificity. RESULTS: We have solved the, X-ray structure of the leucine dehydrogenase from Bacillus sphaericus to a, resolution of 2.2 A. Each subunit of this octameric enzyme contains 364, amino acids and folds into two domains, separated by a deep cleft. The, nicotinamide ring of the NAD+ cofactor binds deep in this cleft, which is, thought to close during the hydride transfer step of the catalytic cycle., CONCLUSIONS: Comparison of the structure of leucine dehydrogenase with a, hexameric glutamate dehydrogenase has shown that these two enzymes share a, related fold and possess a similar catalytic chemistry. A mechanism for, the basis of the differential amino acid specificity between these enzymes, involves point mutations in the amino acid side-chain specificity pocket, and subtle changes in the shape of this pocket caused by the differences, in quaternary structure.
About this Structure
1LEH is a Single protein structure of sequence from Lysinibacillus sphaericus. Active as Leucine dehydrogenase, with EC number 1.4.1.9 Full crystallographic information is available from OCA.
Reference
A role for quaternary structure in the substrate specificity of leucine dehydrogenase., Baker PJ, Turnbull AP, Sedelnikova SE, Stillman TJ, Rice DW, Structure. 1995 Jul 15;3(7):693-705. PMID:8591046
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