[Genetic control of tryptophan hypersynthesis in regulatory mutants of Pseudomonas putida].
The 6-fluorotryptophan resistant MR1 mutant was obtained from Pseudomonas putida M30 (Tyr- Phe-) strain. The mutant was able to excrete tryptophan (60 micrograms/ml) and has derepressed aroF gene encoding 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase. The mutation isolated was identified as aroR with the help of cloning early aroF gene of P. putida. On the next step of selection, regulatory mutant MR2 was obtained producing 240 micrograms/ml of tryptophan. The MR2 has derepressed unlinked trpE and trpDC genes and represents a mutant of the trpR type. Expression of the trpE gene of P. putida MR2 weakened in the presence of tryptophan excess in the medium, which points to attenuation of this gene. From the prototrophic variant of P. putida MR2 the MRP3 mutant producing 850 micrograms/ml of tryptophan was obtained. This mutant was characterized by twofold increase in the activity of the anthranilate synthase encoded by the trpE gene. The assay of the activity of tryptophanyl-tRNA synthase in P. putida MRP3 demonstrated that the mutant has TrpS+ phenotype.
Olekhnovich
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IN
Fomichev
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IuK
D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005798:Genes, Bacterial / Q000235:genetics*; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D011549:Pseudomonas / Q000235:genetics* / Q000378:metabolism; D014364:Tryptophan / Q000096:biosynthesis*
D014364:Tryptophan
Geneticheskiĭ kontrol' sverkhsinteza triptofana u reguliatornykh mutantov Pseudomonas putida.