Topography of the interaction of HPr(Ser) kinase with HPr.

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TitleTopography of the interaction of HPr(Ser) kinase with HPr.
Publication TypeJournal Article
Year of Publication1998
AuthorsZhu, PP, Herzberg, O, Peterkofsky, A
Date Published1998 Aug 25
KeywordsAmino Acid Sequence, Amino Acid Substitution, Asparagine, Bacterial Proteins, Base Sequence, Binding Sites, Escherichia coli, Histidine, Models, Molecular, Molecular Sequence Data, Mutagenesis, Insertional, Mycoplasma, Phosphoenolpyruvate Sugar Phosphotransferase System, Phosphorylation, Protein Kinases, Protein-Serine-Threonine Kinases, Sequence Alignment, Sequence Homology, Amino Acid, Serine

The phosphocarrier protein, HPr, from Gram-positive organisms and mycoplasmas is a substrate for an ATP-dependent kinase that phosphorylates serine 46. In Gram-negative organisms, the corresponding HPr is not phosphorylated on serine 46 and the ATP-dependent kinase is absent. To determine the specificity requirements for phosphorylation of Mycoplasma capricolum HPr, a chimera in which residues 43-57 were replaced by the Escherichia coli sequence was constructed. The chimeric protein folded properly, but was not phosphorylated on either serine 46 or histidine 15. A dissection of the region required for phosphorylation specificity was carried out by further mutagenesis. The deficiency in phosphorylation at histidine 15 was localized primarily to the region including residues 51-57. Activity studies revealed that residues 48, 49, and 51-53 are important for recognition of M. capricolum HPr by its cognate HPr(Ser) kinase. The characteristics of this region suggest that the kinase-HPr interaction occurs mainly through a hydrophobic region. Molecular modeling comparisons of M. capricolum HPr and the chimeric construct provided a basis for interpreting the results of the activity assays.

Alternate JournalBiochemistry
PubMed ID9718298