title: Nucleotide sequence of a mutation in the proB gene of Escherichia coli that confers proline overproduction and enhanced tolerance to osmotic stress.
abstract: We determined the nucleotide (nt) sequence of a mutation that confers proline overproduction and enhanced tolerance of osmotic stress on bacteria. The mutation, designated as proB74, is an allele of the Escherichia coli proB gene which results in a loss of allosteric regulation of the protein product, gamma-glutamyl kinase. Our sequencing indicated that the proB74 mutation is a substitution of an A for a G at nt position 319 of the coding strand of the gene, resulting in a change of an aspartate to an asparagine at amino acid (aa) residue 107 of the predicted protein product. Rushlow et al. [Gene 39 (1984) 109-112] determined that another proB mutation (designated as DHPR), that resulted in a loss of allosteric inhibition by proline of the E. coli gamma-glutamyl kinase, was due to a substitution of an alanine for a glutamate at aa residue 143. Therefore, even though both the DHPR and the proB74 mutations caused a loss of allosteric inhibition of gamma-glutamyl kinase, they are due to different amino acid substitutions.
authors.affiliation: Department of Biological Sciences, Purdue University, W. Lafayette, IN 47907.
authors.forename: L N
authors.initials: LN
authors.lastname: Csonka
authors.forename: S B
authors.initials: SB
authors.lastname: Gelvin
authors.forename: B W
authors.initials: BW
authors.lastname: Goodner
authors.forename: C S
authors.initials: CS
authors.lastname: Orser
authors.forename: D
authors.initials: D
authors.lastname: Siemieniak
authors.forename: J L
authors.initials: JL
authors.lastname: Slightom
mesh_terms: D000483:Alleles; D000494:Allosteric Regulation; D001483:Base Sequence; D003433:Crosses, Genetic; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D005809:Genes, Regulator; D009154:Mutation; D009994:Osmolar Concentration; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D017851:Phosphotransferases (Carboxyl Group Acceptor); D011392:Proline / Q000096:biosynthesis*
chemical_list: D011392:Proline; D010770:Phosphotransferases; D017851:Phosphotransferases (Carboxyl Group Acceptor); C020650:glutamate 5-kinase