[Molecular cloning of threonine biosynthesis genes from Propionibacterium shermanii in Escherichia coli cells].

Cloning the genes for threonine biosynthesis from Propionibacterium shermanii was performed in Escherichia coli cells using the plasmid vector pVZ361. The cloned genes were identified via complementation of thrB, thrC, thrA1 and thrA2 mutations of E. coli. The gene complementing thrB of E. coli was located within a 5.1 kb fragment of P. shermanii chromosomal DNA. The cloned DNA fragment hybridized with a chromosomal fragment of P. shermanii of the same size. The plasmid pSPt4 (with the thrB gene) was digested with Sau3A and ligated with the BamHI-restricted pUC19 vector. The 1.8 kb DNA fragment of P. shermanii was shown to complement the thrB gene function in E. coli cells.