4beq
Structure of Vibrio cholerae broad spectrum racemase double mutant R173A, N174A
Structural highlights
FunctionBSR_VIBCH Amino-acid racemase able to utilize a broad range of substrates. Reversibly racemizes ten of the 19 natural chiral amino acids known, including both non-beta-branched aliphatic amino acids (Ala, Leu, Met, Ser, Cys, Gln and Asn) and positively charged amino acids (His, Lys and Arg). Among these substrates, is the most efficient with lysine and arginine. Is also able to catalyze the racemization of several amino acids that are not typically incorporated into proteins such as ornithine and norleucine. Is not active on negatively charged (Glu and Asp) or aromatic (Tyr, Trp and Phe) amino acids and displays minimal activity towards beta-branched aliphatic (Ile, Val and Thr) substrates (PubMed:24419381). Enables bacteria to produce and release extracellular non-canonical D-amino acids (NCDAAs) that regulate diverse cellular processes which may function as part of a cooperative strategy in vibrio communities to protect non-producing members from competing bacteria (PubMed:29446806, PubMed:29028003). D-amino acid production by BsrV provides a cue for V.cholerae to decrease peptidoglycan synthesis and to alter its cell wall via incorporation of NCDAAs into the muropeptides, in adaption to stationary phase conditions (PubMed:19762646, PubMed:29028003).[1] [2] [3] [4] Publication Abstract from PubMedBroad-spectrum amino-acid racemases (Bsrs) enable bacteria to generate noncanonical D-amino acids, the roles of which in microbial physiology, including the modulation of cell-wall structure and the dissolution of biofilms, are just beginning to be appreciated. Here, extensive crystallographic, mutational, biochemical and bioinformatic studies were used to define the molecular features of the racemase BsrV that enable this enzyme to accommodate more diverse substrates than the related PLP-dependent alanine racemases. Conserved residues were identified that distinguish BsrV and a newly defined family of broad-spectrum racemases from alanine racemases, and these residues were found to be key mediators of the multispecificity of BrsV. Finally, the structural analysis of an additional Bsr that was identified in the bioinformatic analysis confirmed that the distinguishing features of BrsV are conserved among Bsr family members. Structural basis for the broad specificity of a new family of amino-acid racemases.,Espaillat A, Carrasco-Lopez C, Bernardo-Garcia N, Pietrosemoli N, Otero LH, Alvarez L, de Pedro MA, Pazos F, Davis BM, Waldor MK, Hermoso JA, Cava F Acta Crystallogr D Biol Crystallogr. 2014 Jan;70(Pt 1):79-90. doi:, 10.1107/S1399004713024838. Epub 2013 Dec 24. PMID:24419381[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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