RESUMEN
The relative importance of camphor (CAM) plasmid-coded putidaredoxin reductase (PdR) and the chromosome-coded flavin reductases Frp1, Frp2 and Fred for supplying reduced FMN (FNR) to the enantiocomplementary 2,5- and 3,6-diketocamphane monooxygenases (DKCMOs) that are essential for the growth of Pseudomonas putida ATCC 17453 on (rac)-camphor was examined. By undertaking studies in the time window prior to the induction of Fred, and selectively inhibiting Frp1 and 2 with Zn2+, it was confirmed that PdR could serve as the sole active supplier of FNR to the DKCMOs. This establishes for the first time that the CAM plasmid can function as an autonomous extrachromosomal genetic element able to express all the enzymes and redox factors necessary to ensure entry of the C10 bicyclic terpene into the central pathways of metabolism via isobutyryl-CoA.
RESUMEN
For the first time, the differential rates of synthesis of all the key monooxygenases involved in the catabolism by Pseudomonas putida NCIMB 10007 of bicyclic (rac)-camphor to ∆2,5-3,4,4-trimethylpimelyl-CoA, the first aliphatic pathway intermediate, have been determined to help establish the relevant induction profile of each of the oxygen-dependent enzymes. The efficacy of both relevant substrates and pathway metabolites as inducers has been established. Further, inhibitors with characterised functionality have been used to indicate that the pertinent regulatory controls operate at the level of transcription of the corresponding genes.