title: Isolation and characterization of a regulatory mutant of an aminoacyl-transfer ribonucleic acid synthetase in Escherichia coli K-12.
abstract: From Escherichia coli strain K28, which is temperature sensitive for growth because of a mutation in its seryl-transfer ribonucleic acid (tRNA) synthetase gene (serS), temperature-resistant mutants were selected which were found to have a fivefold higher level of seryl-tRNA synthetase than the parent strain. The "high-level" character was found to be genetically stable and is due to a mutation in a locus denoted serO. This locus was found to be very closely linked to serS on the genetic map, and the relative gene order was concluded to be serS-serO-serC. In a serO(-) strain, the normal dependence of seryl-tRNA synthetase (SerRS) activity on changes of exogenous serine concentration was not observed. In a stable heterozygous merodiploid, the serO(-) mutation is still expressed, i.e., it is cis dominant. These results strongly suggest that serO is an operator site involved in the control of the serS gene.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D002474:Cell-Free System; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D004926:Escherichia coli / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D005809:Genes, Regulator; D006358:Hot Temperature; D006877:Hydroxamic Acids / Q000494:pharmacology; D007106:Immune Sera; D009154:Mutation; D012694:Serine / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D006877:Hydroxamic Acids; D007106:Immune Sera; D012694:Serine; D000604:Amino Acyl-tRNA Synthetases