title: Serine sensitivity of Escherichia coli K 12: partial characterization of a serine resistnat mutant that is extremely sensitive to 2-ketobutyrate.
abstract: E. coli wild type bacteria display sensitivity towards serine. A selection medium is described which allows selection of serine resistant mutants. One such mutant is described which presents pleiotropic alterations: it exhibits a thermosensitive growth pattern, alteration in the metabolism of the pppGpp and ppGpp nucleotides, cAMP intracellular level alteration, extreme sensitivity to 2-ketobutyric acid and a defect in the phosphotransferases permeation system. A conjecture explaining these apparently unrelated defects supposes that serine metabolism interferes via phosphoenol pyruvate with a cytoplasmic control of membrane activity (the mutant would be defective in the coupling between membrane and the protein responsible for its cytoplasmic control) and that 2-ketobutyrate is an effector of this activity.
mesh_terms: D002087:Butyrates / Q000494:pharmacology*; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D006158:Guanosine Pentaphosphate / Q000378:metabolism; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D007651:Keto Acids / Q000494:pharmacology; D009154:Mutation; D010641:Phenotype; D012694:Serine / Q000494:pharmacology*
chemical_list: D002087:Butyrates; D003470:Culture Media; D007651:Keto Acids; D006159:Guanosine Tetraphosphate; D006158:Guanosine Pentaphosphate; D012694:Serine; C005087:alpha-ketobutyric acid; D000242:Cyclic AMP