title: Characterization of a phosphatase secreted by Staphylococcus aureus strain 154, a new member of the bacterial class C family of nonspecific acid phosphatases.
abstract: An acid phosphatase, designated SapS, hydrolyzing p-nitrophenyl phosphate (pNPP), was identified and characterized from the culture supernatant of a Staphylococcus aureus strain isolated from vegetables. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the protein indicated an estimated molecular mass of 30 kDa. The enzyme displayed optimum activity at 40 degrees C and pH 5. Characterization of the phosphatase in a reconstitution assay showed that MgCl2 and Triton X-100, respectively, restored maximal activity, but not CaCl2 The phosphatase activity was affected by EDTA and sodium molybdate. The DNA sequence encoding SapS was cloned and sequenced. The putative acid phosphatase gene encodes a protein of 296 amino acids with a 31-residue signal peptide. Database searches revealed significant structural homology of SapS to several proteins belonging to the bacterial class C family of nonspecific acid phosphatases. Comparison of the sequences indicated that despite a low level of overall conservation between the proteins, four conserved sequence motifs could be identified.
authors.affiliation: CSIR-Bio/Chemtek, Pretoria, South Africa.
authors.forename: Erika M
authors.initials: EM
authors.lastname: du Plessis
authors.forename: Jacques
authors.initials: J
authors.lastname: Theron
authors.forename: Lizelle
authors.initials: L
authors.lastname: Joubert
authors.forename: Therese
authors.initials: T
authors.lastname: Lotter
authors.forename: Terry G
authors.initials: TG
authors.lastname: Watson
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis* / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000145:classification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000378:metabolism; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000235:genetics; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D008670:Metals; D000135:Acid Phosphatase