The crystal structure of SdsA1, an alkylsulfatase from Pseudomonas aeruginosa, defines a third class of sulfatases

Pseudomonas aeruginosa is both a ubiquitous environmental bacterium and an opportunistic human pathogen. A remarkable metabolic versatility allows it to occupy a multitude of ecological niches, including wastewater treatment plants and such hostile environments as the human respiratory tract. P. aeruginosa is able to degrade and metabolize biocidic SDS, the detergent of most commercial personal hygiene products. We identify SclsAll of A aeruginosa as a secreted SIDS hydrolase that allows the bacterium to use primary sulfates such as SDS as a sole carbon or sulfur source. Homologues of SdsA1 are found in many pathogenic and some nonpathogenic bacteria. The crystal structure of SdsA1 reveals three distinct domains. The N-terminal catalytic domain with a binuclear Zn2+ cluster is a distinct member of the metallo-beta-lactamase fold family, the central dimerization domain ensures resistance to high concentrations of SIDS, whereas the C-terminal domain provides a hydrophobic groove, presumably to recruit long aliphatic substrates. Crystal structures of apo-SdsAl and complexes with substrate analog and products indicate an enzymatic mechanism involving a water molecule indirectly activated by the Zn2+ cluster. The enzyme SclsAl thus represents a previously undescribed class of sulfatases that allows A aeruginosa to survive and thrive under otherwise bacteriocidal conditions.