title: Influence of phosphoenolpyruvate and magnesium ions on the quaternary structure of enzyme I of the phosphotransferase system from gram-positive bacteria.
abstract: Solution X-ray scattering patterns of enzyme I of the phosphotransferase system from Staphylococcus carnosus indicate an increase in radius of gyration and molecular mass in the presence of Mg2+ or both Mg2+ and phosphoenolpyruvate, indicating a partial dimerization of enzyme I. Mg2+ ions are essential for both the dimerization and the activation, whereas the substrate phosphoenolpyruvate shifts the monomer--dimer equilibrium to the enzymatically active dimer by decreasing the dissociation rate of the phosphorylated dimer.
mesh_terms: D004789:Enzyme Activation; D007700:Kinetics; D046911:Macromolecular Substances; D008274:Magnesium / Q000737:chemistry*; D010728:Phosphoenolpyruvate / Q000737:chemistry*; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000378:metabolism; D017852:Phosphotransferases (Nitrogenous Group Acceptor) / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D012542:Scattering, Radiation; D013210:Staphylococcus / Q000201:enzymology*
chemical_list: D046911:Macromolecular Substances; D010728:Phosphoenolpyruvate; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D017852:Phosphotransferases (Nitrogenous Group Acceptor); C022360:phosphoenolpyruvate-protein phosphotransferase; D008274:Magnesium