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 regulatio n, were obtained with nitrosoguanidine. Investigation of tryptophan bi osynthesis enzyme activity under conditions of excessive and limited t ryptophan demonstrated that the trpE, trpD, and trpC genes from P. men docina and P. marginata are repressed by tryptophan, while the trpF an d trpB genes function constitutively The trpE and trpC genes from P. m endocina were cloned in Escherichia coli in the pBR322 vector. The trp E, trpC, and trpF genes were shown not to be linked to each other. Gen eralizing the data obtained and results of earlier investigations, and taking into account the fact that the first four trp genes are organi zed into two trpE and trpGDC clusters in all known pseudomonads, it co uld be assumed that the P. mendocina and P. marginata trp genes are li nked 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 ).