title: Escherichia coli YrbI is 3-deoxy-D-manno-octulosonate 8-phosphate phosphatase.
abstract: 3-Deoxy-d-manno-octulosonate 8-phosphate (KDO 8-P) phosphatase, which catalyzes the hydrolysis of KDO 8-P to KDO and inorganic phosphate, is the last enzyme in the KDO biosynthetic pathway for which the gene has not been identified. Wild-type KDO 8-P phosphatase was purified from Escherichia coli B, and the N-terminal amino acid sequence matched a hypothetical protein encoded by the E. coli open reading frame, yrbI. The yrbI gene, which encodes for a protein of 188 amino acids, was cloned, and the gene product was overexpressed in E. coli. The recombinant enzyme is a tetramer and requires a divalent metal cofactor for activity. Optimal enzymatic activity is observed at pH 5.5. The enzyme is highly specific for KDO 8-P with an apparent K(m) of 75 microm and a k(cat) of 175 s(-1) in the presence of 1 mm Mg(2+). Amino acid sequence analysis indicates that KDO 8-P phosphatase is a member of the haloacid dehalogenase hydrolase superfamily.
authors.affiliation: Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Woodard
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations; D003001:Cloning, Molecular; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D008956:Models, Chemical; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D002412:Cations; D011994:Recombinant Proteins; D010744:Phosphoric Monoester Hydrolases; C024329:3-deoxy-manno-octulosonate-8-phosphatase; D008274:Magnesium