Mutations in the fusA Gene Encoding Elongation Factor G in the Coryneform Bacterium Lead to Increased Lysine Production

摘要

Resistance to fusidic acid in Corynebacterium glutamicum and Brevibacterium flavum is associated with mutations in the fusA gene, which encodes the elongation factor G (EF-G). Two to ten percent of fusidic acid-resistant clones were shown to produce more lysine than parent strains. Sequencing of the fusA gene in clones with a high level of lysine production made it possible to find two mutations in the gene at position 1383-C1383G and C1383A. These mutations cause amino acid replacement at position 461 in the protein EF-G, namely, histidine is substituted by glutamine (H461Q). The mutation C1383G was introduced in the chromosomal copy of the fusA gene in C. glutamicum and B. flavum strains by homologous recombination. All clones containing the mutant variant of the fusA gene produced 10% more lysine than the parent strains.