Identification of a suppressor gene for the arginine-auxotrophic argJ mutation in Corynebacterium glutamicum.
We recently proposed a metabolic engineering strategy for L-ornithine production based on the hypothesis that an increased intracellular supply of N-acetylglutamate may further enhance L-ornithine production in a well-defined recombinant strain of Corynebacterium glutamicum. In this work, an argJ-deficient arginine auxotrophic mutant of C. glutamicum is suppressed by a different locus of C. glutamicum ATCC13032. Overexpression of the NCgl1469 open reading frame (ORF), exhibiting N-acetylglutamate synthase (NAGS) activity, was able to complement the C. glutamicum arginine-auxotrophic argJ strain and showed increased NAGS activity from 0.03 to 0.17 units mg(-1) protein. Additionally, overexpression of the NCgl1469 ORF resulted in a 39% increase in excreted L-ornithine. These results indicate that the intracellular supply of N-acetylglutamate is a rate-limiting step during L-ornithine production in C. glutamicum.
Hwang
Gui-Hye
GH
Department of Pharmaceutical Engineering, College of Health Science, Sangji University, 660 Woosan-dong, Wonju-si, Gangwon-do, 220-702, Korea.
Cho
Jae-Yong
JY
D051046:Amino-Acid N-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D001120:Arginine / Q000096:biosynthesis*; D003001:Cloning, Molecular; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016153:Genes, Suppressor; D005971:Glutamates; D007700:Kinetics; D009154:Mutation; D016366:Open Reading Frames; D009952:Ornithine / Q000096:biosynthesis*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D005971:Glutamates; D001120:Arginine; D009952:Ornithine; D051046:Amino-Acid N-Acetyltransferase; C016195:N-acetylglutamic acid