title: Phosphorylation of serine-46 in HPr, a key regulatory protein in bacteria, results in stabilization of its solution structure.
abstract: The serine-phosphorylated form of histidine-containing protein (HPr), a component of the phosphoenolpyruvate:sugar phosphotransferase system from Bacillus subtilis, has been characterized by NMR spectroscopy and solvent denaturation studies. The results indicate that phosphorylation of Ser 46, the N-cap of alpha-helix-B, does not cause a conformational change but rather stabilizes the helix. Amide proton exchange rates in helix-B are decreased and phosphorylation stabilizes the protein to solvent and thermal denaturation, with a delta delta G of 0.7-0.8 kcal mol-1. A mutant in which Ser 46 is replaced by aspartic acid shows a similar stabilization, indicating that an electrostatic interaction between the negatively charged groups and the helix macrodipole contributes significantly to the stabilization.
authors.affiliation: Department of Biochemistry, University of Washington, Seattle 98195-7742, USA.
authors.forename: K
authors.initials: K
authors.lastname: Pullen
authors.forename: P
authors.initials: P
authors.lastname: Rajagopal
authors.forename: B R
authors.initials: BR
authors.lastname: Branchini
authors.forename: M E
authors.initials: ME
authors.lastname: Huffine
authors.forename: J
authors.initials: J
authors.lastname: Reizer
authors.forename: M H
authors.initials: MH
authors.lastname: Saier
authors.forename: J M
authors.initials: JM
authors.lastname: Scholtz
authors.forename: R E
authors.initials: RE
authors.lastname: Klevit
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D004355:Drug Stability; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D010766:Phosphorylation; D010768:Phosphoserine / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D010768:Phosphoserine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr