title: A mutant phosphoenolpyruvate carboxykinase in Escherichia coli conferring oxaloacetate decarboxylase activity.
abstract: The phosphoenolpyruvate carboxykinase in Escherichia coli (encoded by pck) catalyzes the conversion from oxaloacetate (OAA) to phosphoenolpyruvate under gluconeogenic conditions. We report here the characterization of two mutant alleles, pck-51 and pck-53, both of which are point mutations leading to single amino acid changes (D to N at position 268 and G to S at position 284, respectively). Pck51 is an altered-activity mutant that catalyzes the conversion from OAA to pyruvate (OAA decarboxylase activity). This new activity was not detected from the wild-type Pck, and it complements the pck null mutation only in a pps+ background. Pck53 is a reduced-activity mutant that complements the pck null mutation in a strain-dependent fashion.
authors.affiliation: Department of Chemical Engineering, Texas A&M University, College Station 77843-3122.
authors.forename: S Y
authors.initials: SY
authors.lastname: Hou
authors.forename: Y P
authors.initials: YP
authors.lastname: Chao
authors.forename: J C
authors.initials: JC
authors.lastname: Liao
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002262:Carboxy-Lyases / Q000378:metabolism; D003653:Decarboxylation; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010071:Oxaloacetates / Q000378:metabolism*; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics*; D017354:Point Mutation; D012689:Sequence Homology, Nucleic Acid; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D010071:Oxaloacetates; D002262:Carboxy-Lyases; C021916:oxaloacetate decarboxylase; D010729:Phosphoenolpyruvate Carboxykinase (GTP)