title: The Streptococcus thermophilus protein Wzh functions as a phosphotyrosine phosphatase.
abstract: Amino acid residues that are important for metal binding and catalysis in Gram-positive phosphotyrosine phosphatases were identified in the Wzh protein of Streptococcus thermophilus MR-1C by using sequence comparisons. A His-tagged fusion Wzh protein was purified from Escherichia coli cultures and tested for phosphatase activity against synthetic phosphotyrosine and phosphoserine-threonine peptides. Purified Wzh released 2316.5 ± 138.7 pmol PO4·min(-1)·μg(-1) from phosphotyrosine peptide-1 and 2345.7 ± 135.2 pmol PO4·min(-1)·μg(-1) from phosphotyrosine peptide-2. The presence of the phosphotyrosine phosphatase inhibitor sodium vanadate decreased purified Wzh activity by 45%-50% at 1 mmol·L(-1), 74%-84% at 5 mmol·L(-1), and by at least 88% at 10 mmol·L(-1). Purified Wzh had no detectable activity against the phosphoserine-threonine peptide. These results clearly establish that S. thermophilus MR-1C Wzh functions as a phosphotyrosine phosphatase that could function to remove phosphate groups from proteins involved in exopolysaccharide biosynthesis, including the protein tyrosine kinase Wze and priming glycosyltransferase.
authors.affiliation: Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA. ACefalo@biology.usu.edu
authors.forename: Angela D
authors.initials: AD
authors.lastname: Cefalo
authors.forename: Jeffery R
authors.initials: JR
authors.lastname: Broadbent
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Welker
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D048249:Streptococcus thermophilus / Q000201:enzymology* / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D010455:Peptides; D011993:Recombinant Fusion Proteins; D010768:Phosphoserine; D019000:Phosphotyrosine; D014638:Vanadates; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases