[Cloning of the recA gene of the propionic acid bacterium Propionibacterium shermanii in Escherichia coli cells].

Propionibacterium are producers of vitamin B-12 and organic acids and are of importance in national economy. Genetics of this organism was studied insufficiently. We constructed the genomic library of Propionibacterium shermanii in cells of Escherichia coli using the plasmid vector pVZ361 and identified recA gene. The vector gives a chance for direct selection of Str-resistant clones containing an insert in BamHI site. The recombinant plasmid carrying the recA gene of P. shermanii was isolated from the genomic library using complementation in E. coli. Strains E. coli C600 and HB101 were transformed by hybrid plasmids, and UV-light-resistant clones were identified. The clones were purified and subjected to treatment with 4-NQO and MMS. Diagrams reflecting survival dependence of the bacteria carrying recombinant plasmids and lacking them on the mutagen concentration and UV-light dose clearly confirmed functioning of P. shermanii recA gene in E. coli cells. The insert with recA gene underwent restriction analysis. The 1.7 kb fragment with recA gene was then transferred to pBI101 plasmid and the resultant recombinant plasmid was used in the SOS test. The mutagens (MMS, 4-NHQ) and UV-light induced the SOS response in E. coli HB101 (recA) carrying the recombinant plasmid.