7agz
BsrV no-histagged
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 non-canonical D-amino acids (NCDAAs), whose roles and impact on microbial physiology, including modulation of cell wall structure and dissolution of biofilms, are just beginning to be appreciated. Here we used a diverse array of structural, biochemical and molecular simulation studies to define and characterize how BsrV is post-translationally regulated. We discovered that contrary to Vibrio cholerae alanine racemase AlrV highly compacted active site, BsrV's is broader and can be occupied by cell wall stem peptides. We found that peptidoglycan peptides modified with NCDAAs are better stabilized by BsrV's catalytic cavity and show better inhibitory capacity than canonical muropeptides. Notably, BsrV binding and inhibition can be recapitulated by undigested peptidoglycan sacculi as it exists in the cell. Docking simulations of BsrV binding the peptidoglycan polymer generate a model where the peptide stems are perfectly accommodated and stabilized within each of the dimers active sites. Taking these biochemical and structural data together, we propose that inhibition of BsrV by peptidoglycan peptides underlies a negative regulatory mechanism to avoid excessive NCDAA production. Our results collectively open the door to use "a la carte" synthetic peptides as a tool to modulate DAAs production of Bsr enzymes. Binding of non-canonical peptidoglycan controls Vibrio cholerae broad spectrum racemase activity.,Espaillat A, Carrasco-Lopez C, Bernardo-Garcia N, Rojas-Altuve A, Klett J, Morreale A, Hermoso JA, Cava F Comput Struct Biotechnol J. 2021 Jan 26;19:1119-1126. doi:, 10.1016/j.csbj.2021.01.031. eCollection 2021. PMID:33680355[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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