title: Biosynthetic regulation of individual proteins in relA+ and relA strains of Escherichia coli during amino acid starvation.
abstract: An isogenic pair of Escherichia coli mutants (relA+ tufB valSts and relA1 tufB valSts) has been cultured at several temperatures to establish various degrees of limitation for valyl-tRNA synthetase. The biosynthetic rate of 16 identifiable proteins, most of which are components of the transcription and translation apparatus, was measured by pulse-labelling with [35S]-methionine, followed by protein separation using two-dimensional gel electrophoresis (O'Farrell, 1975). No single pattern of response to amino acid starvation of biosynthetic rate was observed. EF-Ts, L12 and S6 were found to be under strong stringent and relaxed regulation; EF-G, EF-Tu-A and S1 are under strong stringent, but weak relaxed regulation; EF-Tu-B, alpha, VRS, IRS and ARS are under week stringent and weak relaxed regulation; beta is under weak stringent regulation and does not respond at all to relaxed conditions; the biosynthetic rate of a protein called stringent starvation protein is strongly stimulated, relative to other proteins, in the starved stringent strain.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D004926:Escherichia coli / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000096:biosynthesis; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis; D014176:Protein Biosynthesis; D013045:Species Specificity; D014158:Transcription, Genetic; D014498:Uracil / Q000378:metabolism; D014633:Valine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D006150:Guanine Nucleotides; D010446:Peptide Fragments; D014498:Uracil; D007930:Leucine; D014633:Valine