[Cloning and structural-functional analysis in Escherichia coli of genes of glutamate-producing corynebacteria controlling biosynthesis of amino acids of aspartic acid series].

A library of EcoRI DNA fragments from Brevibacterium flavum was constructed using plasmid vector. The genes complementing ThrA2 and ThrB mutations in Escherichia coli were identified in the library. The gene thrA2 of B. flavum codes for mutant enzyme homoserine dehydrogenase insensitive to inhibition by threonine. The genes thrA2 and thrB are localized wihtin the EcoRI fragment 4.1 kb long and are expressed under the control of their own promoters in E. coli cells. Structural and functional analysis of cloned C. glutamicum gene ilvA was performed. The gene of C. glutamicum complemented ilvA mutation in E. coli and appeared to be localized within the EcoRI--SacI DNA fragment 1.6 kb in size. Using E. coli minicells we have demonstrated that the gene ilvA of C. glutamicum controls the synthesis of polypeptide of relative molecular mass 50 kD.