Identification of phosphoproteins in Escherichia coli.
The substrates of ion- and lipid-stimulated protein kinase activity in extracts of Escherichia coli were purified by chromatography. Subsequent N-terminal sequencing suggests that these substrates include the following: a novel 80 kDa protein co-purifying with RNA polymerase but partially homologous to elongation factor G; a protein with an apparent molecular weight of 65 kDa identified as the ribosomal protein S1; and a 32 kDa protein identified as succinyl CoA synthetase, a key enzyme in the tricarboxylic acid cycle. The phosphorylation of these three proteins was markedly stimulated by the addition of manganese, and occurred on threonine, serine or tyrosine residues as indicated by the stability of the phosphoresidues during acid treatment. In addition, a calcium-stimulated protein of 70 kDa was identified as the heat-shock protein DnaK, and a 17 kDa lipid-stimulated phosphoprotein as nucleotide diphosphate kinase.
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Department of Microbiology and Immunology, University of Leicester, UK.
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Toth
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Norris
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D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000302:isolation & purification* / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006160:Guanosine Triphosphate / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism; D010750:Phosphoproteins / Q000302:isolation & purification* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012269:Ribosomal Proteins / Q000378:metabolism; D015398:Signal Transduction; D013389:Succinate-CoA Ligases / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D010750:Phosphoproteins; D012269:Ribosomal Proteins; C015494:ribosomal protein S1; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D009701:Nucleoside-Diphosphate Kinase; C063842:dnaK protein, E coli; D013389:Succinate-CoA Ligases; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium