title: Regulatory mutations affecting the gluconate system in Escherichia coli.
abstract: A spontaneously arising regulatory mutant of the gluconate system in Escherichia coli was isolated. This mutant became constitutive, probably in one step, for gluconate high-affinity transport, gluconokinase, and gluconate-6-P dehydrase. The mutation involved (gntR18) is cotransducible with asd. Pseudorevertants, derived from a mutant (M2) that shows a long lag for growth on gluconate mineral medium, were also isolated and characterized. They give constitutive levels of gluconokinase and gluconate-6-P dehydrase but lack high-affinity transport function. Genetic experiments performed with one of these pseudorevertants (M4) indicate that it carries a secondary mutation in the gntR gene. The M4 phenotype is thus the result of the interaction of expression of a constitutive mutation (gntR4) with the mutation of strain M2 (gntM2).
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D002247:Carbon Isotopes; D002874:Chromosome Mapping; D003470:Culture Media; D004926:Escherichia coli / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D005796:Genes; D005942:Gluconates / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006867:Hydrolases / Q000378:metabolism; D009154:Mutation; D010770:Phosphotransferases / Q000378:metabolism; D011995:Recombination, Genetic; D014161:Transduction, Genetic
chemical_list: D002247:Carbon Isotopes; D003470:Culture Media; D005942:Gluconates; D010770:Phosphotransferases; D006867:Hydrolases; D005947:Glucose