The OCT plasmid encodes D-lysine membrane transport and catabolic enzymes in Pseudomonas putida

Pseudomonas putida (oleovorans) (Pp(OCT)) cured of its OCT plasmid (Pp) no longer grows on D-lysine. Conjugation of PpTrp- with three different methionine auxotrophs carrying the OCT plasmid resulted in PpTrp- (OCT) organisms that grew on D-lysine. Three early D-lysine catabolic enzymes encoded by the OCT plasmid are a lysine racemase, the proposed conversion of D-lysine to delta 1-piperidine-2-carboxylate (P2C), for which we provide evidence, and P2C reductase which converts P2C to pipecolate. In Pp the rate of active D-lysine transport is reduced by 30 to 50%. We consider this to reflect a loss of the gene for the D-lysine carrier while the remaining activity is due to a chromosomally coded L-lysine or D-ornithine carrier or both. The membrane carriers and catabolic enzymes for D- and L-lysine in P. putida P2 and for L-lysine in Pp(OCT) are chromosomally coded.