The sulfur-regulated arylsulfatase gene cluster of Pseudomonas aeruginosa,a new member of the cys regulon

A gene cluster upstream of the arylsulfatase gene (atsA) in Pseudomonas aer uginosa was characterized and found to encode a putative ABC-type transport er, AtsRBC. Mutants with insertions in the atsR or atsB gene were unable to grow with hexyl-, octyl-, or nitrocatecholsulfate, although they grew norm ally with other sulfur sources, such as sulfate, methionine, and aliphatic sulfonates. AtsRBC therefore constitutes a general sulfate ester transport system, and desulfurization of aromatic and medium-chain-length aliphatic s ulfate esters occurs in the cytoplasm. Expression of the atsR and atsBCA ge nes was repressed during growth with sulfate, cysteine, or thiocyanate. No expression of these genes was observed in the cysB mutant PAO-CB, and the a ts genes therefore constitute an extension of the cys regulon in this speci es.