Regulation of tryptophan biosynthesis in Pseudomonas mendocina and Pseudomonas marginata bacteria

The basic tryptophan-dependent mutants of Pseudomonas mendocina and P. marginata, which were used to study tryptophan biosynthesis regulation, were obtained with nitrosoguanidine. Investigation of tryptophan biosynthesis enzyme activity under conditions of excessive and limited tryptophan demonstrated that the trpE, trpD, and trpC genes from P. mendocina and P. marginata are repressed by tryptophan, while the trpF and trpB genes function constitutively The trpE and trpC genes from P. mendocina were cloned in Escherichia coli in the pBR322 vector. The trpE, trpC, and trpF genes were shown not to be linked to each other. Generalizing the data obtained and results of earlier investigations, and taking into account the fact that the first four trp genes are organized into two trpE and trpGDC clusters in all known pseudomonads, it could be assumed that the P. mendocina and P. marginata trp genes are linked in the following clusters: trpE, trpGDC, trpF, and trpBA. This is the difference between these bacteria and the other bacterial species studied in this respect (P. putida, P. aeruginosa, and P. acidovorans).