PmpAB proteins are associated with proteins involved in sulfur metabolism, and members of the pigS-pmpABC and blhA-orfY system are frequently associated. (A) Phylogenomic profile of functions related to COG2391 (PmpAB; DUF395) shows possible interactions generated in STRING (high confidence, 10 top interactors shown). Shown are COG0425 (SirA), a predicted regulator of disulfide bond formation; COG2895, GTPase-sulfate adenylate transferase subunit 1; COG4208, ABC-type sulfate transport system, permease component; COG0031, cysteine synthase; COG0175, 3-phosphoadenosine 5-phosphosulfate sulfotransferase; COG0529, adenylylsulfate kinase and related kinases; COG1118, ABC-type sulfate/molybdate transport systems, ATPase component; COG0155, sulfite reductase, beta subunit (hemoprotein); COG4150, ABC-type sulfate transport system, periplasmic component; and COG0369, sulfite reductase, alpha subunit (flavoprotein). (B) Putative functional interactions between all six domain members of the blhA-orfY and pigS-pmpABC operons. In both panels A and B, the thickness of the lines relates to the degree of confidence in an association.