title: Sequence homologies between proteins of bacterial phosphoenolpyruvate-dependent sugar phosphotransferase systems: identification of possible phosphate-carrying histidine residues.
abstract: The DNA sequences for some of the genes involved in the phosphoenolpyruvate-dependent phosphotransferase system (PTS) of Escherichia coli and Salmonella typhimurium have been reported. Comparison of the deduced amino acid sequences of enzyme IIBgi, enzyme IIMtl, and enzyme IIGlc/enzyme IIIGlc, which catalyze the uptake and concomitant phosphorylation of beta-glucosides, mannitol, and glucose, respectively, reveals considerable sequence homology. In particular, the carboxyl-terminal region of enzyme IIBgl is so homologous to the whole of enzyme IIIGlc as to suggest a common function. We postulate that His-547 of enzyme IIBgl receives a phosphate group directly from the cytoplasmic protein HPr and transfers this phosphate to His-306 located in the amino-terminal half of enzyme IIBgl. This latter histidine is conserved in enzyme IIBgl and enzyme IIGlc and, in both proteins, occurs in a region that shows homology with the His-15 region of HPr, which is known to act as the phosphate carrier. An equivalent histidine residue, His-195, is also present in enzyme IIMtl, although here the flanking sequence is different. None of these specified histidine residues is likely to be buried within the membrane.
authors.forename: H F
authors.initials: HF
authors.lastname: Bramley
authors.forename: H L
authors.initials: HL
authors.lastname: Kornberg
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D006639:Histidine / Q000031:analogs & derivatives; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics*; D010766:Phosphorylation; D012486:Salmonella typhimurium / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D012984:Software; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D006639:Histidine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C005436:phosphohistidine