1hdh
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ARYLSULFATASE FROM PSEUDOMONAS AERUGINOSA
OverviewOverview
BACKGROUND: Sulfatases constitute a family of enzymes with a highly, conserved active site region including a Calpha-formylglycine that is, posttranslationally generated by the oxidation of a conserved cysteine or, serine residue. The crystal structures of two human arylsulfatases, ASA, and ASB, along with ASA mutants and their complexes led to different, proposals for the catalytic mechanism in the hydrolysis of sulfate esters., RESULTS: The crystal structure of a bacterial sulfatase from Pseudomonas, aeruginosa (PAS) has been determined at 1.3 A. Fold and active site region, are strikingly similar to those of the known human sulfatases. The, structure allows a precise determination of the active site region, unequivocally showing the presence of a Calpha-formylglycine hydrate as, the key catalytic residue. Furthermore, the cation located in the active, site is unambiguously characterized as calcium by both its B value and the, geometry of its coordination sphere. The active site contains a, noncovalently bonded sulfate that occupies the same position as the one in, para-nitrocatecholsulfate in previously studied ASA complexes., CONCLUSIONS: The structure of PAS shows that the resting state of the key, catalytic residue in sulfatases is a formylglycine hydrate. These, structural data establish a mechanism for sulfate ester cleavage involving, an aldehyde hydrate as the functional group that initiates the reaction, through a nucleophilic attack on the sulfur atom in the substrate. The, alcohol is eliminated from a reaction intermediate containing, pentacoordinated sulfur. Subsequent elimination of the sulfate regenerates, the aldehyde, which is again hydrated. The metal cation involved in, stabilizing the charge and anchoring the substrate during catalysis is, established as calcium.
About this StructureAbout this Structure
1HDH is a Single protein structure of sequence from Pseudomonas aeruginosa with CA and SO4 as ligands. Active as Arylsulfatase, with EC number 3.1.6.1 Structure known Active Site: CA1. Full crystallographic information is available from OCA.
ReferenceReference
1.3 A structure of arylsulfatase from Pseudomonas aeruginosa establishes the catalytic mechanism of sulfate ester cleavage in the sulfatase family., Boltes I, Czapinska H, Kahnert A, von Bulow R, Dierks T, Schmidt B, von Figura K, Kertesz MA, Uson I, Structure. 2001 Jun;9(6):483-91. PMID:11435113
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