title: Isolation and partial characterization of Rhodopseudomonas sphaeroides mutants defective in the regulation of ribulose bisphosphate carboxylase/oxygenase.
abstract: Several mutants of Rhodopseudomonas sphaeroides defective in the derepression of the enzyme ribulose 1,5-bisphosphate carboxylase have been isolated by using the unstable Tn5 vectors pJB4JI and pRK340. Transpositional insertion mutants obtained with pJB4JI were demonstrated to be incapable of increasing ribulose 1,5-bisphosphate carboxylase/oxygenase levels when grown on butyrate-bicarbonate medium or under conditions of carbon starvation, whereas the wild-type strain increased activity four- to eightfold. When the wild-type strain was starved for carbon in the presence of chloramphenicol, no derepression was observed. Crude extracts from mutant and wild-type strains had distinct and consistent differences in protein content as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Chromatographic evidence indicated that mutants were defective in the regulation of only one of the two forms of ribulose 1,5-bisphosphate carboxylase/oxygenase synthesized by R. sphaeroides.
mesh_terms: D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D005822:Genetic Vectors; D007700:Kinetics; D009154:Mutation; D010957:Plasmids; D012242:Rhodobacter sphaeroides / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics*; D013045:Species Specificity
chemical_list: D004251:DNA Transposable Elements; D012273:Ribulose-Bisphosphate Carboxylase