원문정보
초록
영어
Minimization of a genome provides many advantages over conventional approaches. Targeted deletion of large blocks of unnecessary genes can reduce production of unwanted by-products, and increase genome stability while simultaneously streamlining or simplifiing metabolism without physiological compromise. Recently, a reduced-genome Escherichia coli strain,
MDS42 (Science, 312, 1044-1046) lacking 14.3% of the chromosome has been constructed. The reduced-genome E. coli has been reengineered to increase the productivity of an essential amino acid L-threonine, by over-expressing a feedback resistant threonine operon (thrA*BC), deleting the genes encoding threonine dehydrogenase (tdh) and threonine transporter (tdcC and sstT), and introducing a mutant threonine exporter (rhtA23). The resulting strain, MDS42-thr, shows a 20% increase in threonine production relative to the wildtype E. coli strain engineered with the same threonine specific modifications. This result clearly demonstrates that elimination of large numbers of genes unnecessary for cell growth from the genome can increase the productivity of the strain significantly, most likely by reducing the metabolic burden on the
cells.