title: Specific amino acid residues in both the PstB and PstC proteins are required for phosphate transport by the Escherichia coli Pst system.
abstract: Three mutant alleles of the pstC gene and one mutant allele of the pstB gene were produced by site-directed mutagenesis. The pstC gene encodes an integral membrane protein of the phosphate-specific transport (Pst) system of Escherichia coli. The amino acid substitutions resulting from the pstC gene mutations, Arg-237----Gln, Glu-240----Gln, or a combination of both, caused the loss of phosphate transport through the Pst system, but the alkaline phosphatase activity remained repressed. The pstB gene encodes a peripheral membrane protein of the Pst system which carries a putative nucleotide-binding site. The amino acid substitutions Gly-48----Ile and Lys-49----Gln, resulting from the pstB mutations, caused the loss of phosphate transport through the Pst system and the derepression of alkaline phosphatase activity. The residues Gly-48 and Lys-49 are key residues in the putative nucleotide-binding site.
authors.affiliation: Division of Biochemical Sciences, John Curtin School of Medical Research, Australian National University, Canberra City A.C.T.
authors.forename: G B
authors.initials: GB
authors.lastname: Cox
authors.forename: D
authors.initials: D
authors.lastname: Webb
authors.forename: H
authors.initials: H
authors.lastname: Rosenberg
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000483:Alleles; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D028044:Phosphate-Binding Proteins; D010710:Phosphates / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D015345:Oligonucleotide Probes; D028044:Phosphate-Binding Proteins; D010710:Phosphates; D000469:Alkaline Phosphatase