| Comment | By homology, members are Zn metallohydrolases in the same family as the SoxH protein associated with sulfate metabolism, Bacillus cereus beta-lactamase II (see PDB:1bc2), and, more distantly, hydroxyacylglutathione hydrolase (glyoxalase II). All members occur in genomes with both PQQ biosynthesis and a PQQ-dependent (quinoprotein) dehydrogenase that has a motif of two consecutive Cys residues (see TIGR03075). The Cys-Cys motif is associated with electron transfer by specialized cytochromes such as c551. All these genomes also include a fusion protein (TIGR04557) whose domains resemble SoxY and SoxZ from thiosulfate oxidation. A conserved Cys in this fusion protein aligns to the Cys residue in SoxY that carries sulfur cycle intermediates. In many genomes, the genes for PQQ biosynthesis enzymes, PQQ-dependent enzymes, their associated cytochromes, and members of this family are clustered. Note that one to three closely related Zn metallohydrolases may occur; this family represents a specific clade among them. |
