This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Nakamura, J.
Right arrow Articles by Wachi, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nakamura, J.
Right arrow Articles by Wachi, M.
Agricola
Right arrow Articles by Nakamura, J.
Right arrow Articles by Wachi, M.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, July 2007, p. 4491-4498, Vol. 73, No. 14
0099-2240/07/$08.00+0     doi:10.1128/AEM.02446-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Mutations of the Corynebacterium glutamicum NCgl1221 Gene, Encoding a Mechanosensitive Channel Homolog, Induce L-Glutamic Acid Production{triangledown}

Jun Nakamura,1,2 Seiko Hirano,1 Hisao Ito,1 and Masaaki Wachi2*

Fermentation & Biotechnology Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan,1 Department of Bioengineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan2

Received 18 October 2006/ Accepted 14 May 2007

Corynebacterium glutamicum is a biotin auxotroph that secretes L-glutamic acid in response to biotin limitation; this process is employed in industrial L-glutamic acid production. Fatty acid ester surfactants and penicillin also induce L-glutamic acid secretion, even in the presence of biotin. However, the mechanism of L-glutamic acid secretion remains unclear. It was recently reported that disruption of odhA, encoding a subunit of the 2-oxoglutarate dehydrogenase complex, resulted in L-glutamic acid secretion without induction. In this study, we analyzed odhA disruptants and found that those which exhibited constitutive L-glutamic acid secretion carried additional mutations in the NCgl1221 gene, which encodes a mechanosensitive channel homolog. These NCgl1221 gene mutations lead to constitutive L-glutamic acid secretion even in the absence of odhA disruption and also render cells resistant to an L-glutamic acid analog, 4-fluoroglutamic acid. Disruption of the NCgl1221 gene essentially abolishes L-glutamic acid secretion, causing an increase in the intracellular L-glutamic acid pool under biotin-limiting conditions, while amplification of the wild-type NCgl1221 gene increased L-glutamate secretion, although only in response to induction. These results suggest that the NCgl1221 gene encodes an L-glutamic acid exporter. We propose that treatments that induce L-glutamic acid secretion alter membrane tension and trigger a structural transformation of the NCgl1221 protein, enabling it to export L-glutamic acid.

* Corresponding author. Mailing address: Department of Bioengineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan. Phone: 81-45-924-5770. Fax: 81-45-924-5820. E-mail: mwachi{at}bio.titech.ac.jp

{triangledown} Published ahead of print on 18 May 2007.

Applied and Environmental Microbiology, July 2007, p. 4491-4498, Vol. 73, No. 14
0099-2240/07/$08.00+0     doi:10.1128/AEM.02446-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Sano, C. (2009). History of glutamate production. Am. J. Clin. Nutr. 90: 728S-732S [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»