title: Deamidation of HPr, a phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system, involves asparagine 38 (HPr-1) and asparagine 12 (HPr-2) in isoaspartyl acid formation.
abstract: Histidine-containing protein, HPr, of the phosphoenolpyruvate:sugar phosphotransferase system in Escherichia coli, when incubated at elevated temperatures forms many species of protein. The two major species are HPr-1 and HPr-2, which have been shown to lack one or two amides, respectively (Anderson, B., Weigel, N., Kundig, W., and Roseman, S. (1971) J. Biol. Chem. 246, 7023-7033). The formation of HPr-1 and HPr-2 is shown to be pH-dependent and does not occur readily below pH 6. Investigation of the identities and properties of the two residues that deamidate involved creation of site-directed mutants at the 6 glutamine and 2 asparagine residues of HPr; description of their deamidation species by isoelectric focusing; determination of their relative antibody binding properties; assay of their phosphoacceptor and phosphodonor activities; characterization of tryptic and V8-protease peptides; obtaining two-dimensional nuclear magnetic resonance spectra of HPr, HPr-1, and several mutants. It was determined that the sequential deamidation of Asn-38 and Asn-12 yields HPr-1 and HPr-2. Both residues exist as Asn-Gly pairs, and both deamidations probably form isoaspartyl acid. HPr from Bacillus subtilis and Staphylococcus carnosus which also have Asn-Gly at residues 38 and 39 form HPr-1 species presumably by deamidation. HPr from Streptococcus faecalis which does not have Asn-38 does not form a HPr-1 species. The E. coli mutant HPrs, N12D and Q51E, residues that may be involved in the active site, had impaired phosphohydrolysis properties and decreased phosphoenolpyruvate:sugar phosphotransferase system activity.
authors.affiliation: Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Sharma
authors.forename: P K
authors.initials: PK
authors.lastname: Hammen
authors.forename: J W
authors.initials: JW
authors.lastname: Anderson
authors.forename: A
authors.initials: A
authors.lastname: Leung
authors.forename: F
authors.initials: F
authors.lastname: Georges
authors.forename: W
authors.initials: W
authors.lastname: Hengstenberg
authors.forename: R E
authors.initials: RE
authors.lastname: Klevit
authors.forename: E B
authors.initials: EB
authors.lastname: Waygood
mesh_terms: D000595:Amino Acid Sequence; D001216:Asparagine; D001224:Aspartic Acid / Q000378:metabolism*; D001412:Bacillus subtilis / Q000201:enzymology; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D010450:Endopeptidases; D013293:Enterococcus faecalis / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments / Q000302:isolation & purification; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013210:Staphylococcus / Q000201:enzymology; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D001224:Aspartic Acid; D001216:Asparagine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D010450:Endopeptidases