Identification of orthologs for H₂S-producing enzymes in V. cholerae.

(A). CBS orthologs. Left panel, domain architectures of CBS proteins are presented. In CBS proteins, the catalytic core domain PALP (pfam00291) is highly conserved across phyla [28]. There are three PALP-containing proteins in V. cholerae, encoding by vc1061, vc0968, and vc0537, respectively. Right panel, multiple sequence alignment (MSA) of PALP regions, showing that all the three CBS candidate proteins in V. cholerae have the active-site loop residues of CBS (outlined with red) [25,27–29]. However, only VC1061 processes the key site for the function of H₂S biogenesis reported by Devi et al. 2017 [28] (red asterisk). (B). CSE orthologs. Cys/Met metabolism PLP-dependent domain (Cys_Met_Meta_PP, pfam01053) is the conserved domain in CSE proteins. V. cholerae encodes two Cys_Met_Meta_PP enzymes VC2683 and VC1671. Red and blue asterisks indicate key active-site residues in binging with co-factor pyridoxal-5’-phosphate (PLP) and inhibitor DL-propargylglycine (PAG), respectively [26]. VC1671 is not a CSE homolog, since it lacks four key active-site residues (shaded with yellow). (C). 3MST orthologs. Active-site loop residues of 3MST are shown in red [17]. Hsa, Homo sapiens; Dme, Drosophila melanogaster; Sce, Saccharomyces cerevisiae S288C; Bat, Bacillus anthracis str. Sterne; Eco, Escherichia coli; Ype, Yersinia pestis CO92; Stm, Salmonella typhimurium LT2; Vch, V. cholerae.

(PDF)