The solution structure of the histidine-containing protein (HPr) from Staphylococcus aureus as determined by two-dimensional 1H-NMR spectroscopy

The three-dimensional solution structure of the heat-stable phosphocarrier protein HPr from Staphylococcus aureus was determined from two-dimensional NMR data by restrained molecular dynamics. It consists of a large twisted antiparallel β-pleated sheet with four strands A, B, C, and D of amino acids 2–7, 34–37, 40–42 and 60–65. Three right-handed helices A, B, C (amino acids 18–27, 47–53 and 71–85) are positioned on top of this sheet. The aromatic ring of His15 is located in a cleft formed by amino acids 12–17 and 55–58, only the nitrogen (Nδ1) atom which can be phosphorylated by enzyme I is exposed to the water. The side chains of Thr12 and Arg17 are located close to the histidine ring. The regulatory serine residue (Ser46) is located in a hydrophobic patch, its hydroxyl group is water-accessible but forms hydrogen bonds with the amide groups of the backbone. The general features of the three-dimensional structure are similar to those found in HPr proteins from different microorganisms such as Escherichia coli, Bacillus subtilis and Streptococcus faecalis