Recombinant Vibrio cholerae serotype O1 Alanine racemase 2 (alr2)

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. 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. 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.