2dab
From Proteopedia
L201A MUTANT OF D-AMINO ACID AMINOTRANSFERASE COMPLEXED WITH PYRIDOXAL-5'-PHOSPHATE
Structural highlights
Function[DAAA_BACYM] Acts on the D-isomers of alanine, leucine, aspartate, glutamate, aminobutyrate, norvaline and asparagine. The enzyme transfers an amino group from a substrate D-amino acid to the pyridoxal phosphate cofactor to form pyridoxamine and an alpha-keto acid in the first half-reaction. The second-half reaction is the reverse of the first, transferring the amino group from the pyridoxamine to a second alpha-keto acid to form the product D-amino acid via a ping-pong mechanism. This is an important process in the formation of D-alanine and D-glutamate, which are essential bacterial cell wall components.[1] [2] 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 PubMedThe leucine-to-alanine mutation at residue 201 of D-amino acid aminotransferase provides a unique enzyme which gradually loses its activity while catalyzing the normal transamination; the co-enzyme form is converted from pyridoxal 5'-phosphate to pyridoxamine 5'-phosphate upon the inactivation [Kishimoto,K., Yoshimura,T., Esaki,N., Sugio,S., Manning,J.M. and Soda,K. (1995) J. Biochem., 117, 691-696]. Crystal structures of both co-enzyme forms of the mutant enzyme have been determined at 2.0 A resolution: they are virtually identical, and are quite similar to that of the wild-type enzyme. Significant differences in both forms of the mutant are localized only on the bound co-enzyme, the side chains of Lys145 and Tyr31, and a water molecule sitting on the putative substrate binding site. Detailed comparisons of the structures of the mutant, together with that of the pyridoxamine-5'-phosphate form of the wild-type enzyme, imply that Leu201 would play a crucial role in the transamination reaction by keeping the pyridoxyl ring in the proper location without disturbing its oscillating motion, although the residue seems to not be especially important for the structural integrity of the enzyme. Crystal structures of L201A mutant of D-amino acid aminotransferase at 2.0 A resolution: implication of the structural role of Leu201 in transamination.,Sugio S, Kashima A, Kishimoto K, Peisach D, Petsko GA, Ringe D, Yoshimura T, Esaki N Protein Eng. 1998 Aug;11(8):613-9. PMID:9749913[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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