title: Increased L-ornithine production in Corynebacterium glutamicum by overexpression of a gene encoding a putative aminotransferase.
abstract: Overexpression of the NCgl0462 open reading frame, encoding a class II aminotransferase, was studied in conjunction with other enzymes in L-ornithine biosynthesis in an L-ornithine-producing strain. Expression of the wild-type NCgl0462 open reading frame, which displayed aminotransferase activity, was amplified by placing it under the control of the glyceraldehyde 3-phosphate dehydrogenase gene promoter in the pEK0 plasmid and in the genome. L-Ornithine production in Corynebacterium glutamicum SJC8260 harboring plasmid and the genomic NCgl0462 open reading frame was increased by 8.8 and 21.6%, respectively. In addition, the combined overexpression of the NCgl0462 open reading frame within the genome along with the mutated L-ornithine biosynthesis genes (argCJBD) placed in the pEK0 plasmid in C. glutamicum SJC8260 resulted in significant improvement in L-ornithine production (12.48 g/l for combined overexpression compared with 8.42 g/l for the control). These results suggest that overexpression of the aminotransferase-encoding NCgl0462 open reading frame plays an unequivocal role in the L-ornithine biosynthetic pathway, with overlapping substrate specificity in C. glutamicum.
authors.forename: Dai-Joong
authors.initials: DJ
authors.lastname: Kim
authors.forename: Gui-Hye
authors.initials: GH
authors.lastname: Hwang
authors.forename: Ji-Na
authors.initials: JN
authors.lastname: Um
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Cho
mesh_terms: D002473:Cell Wall / Q000737:chemistry; D048230:Corynebacterium glutamicum / Q000201:enzymology* / Q000378:metabolism*; D018628:Gene Dosage; D015870:Gene Expression; D009952:Ornithine / Q000378:metabolism*; D010957:Plasmids; D000637:Transaminases / Q000235:genetics / Q000378:metabolism*
chemical_list: D009952:Ornithine; D000637:Transaminases