This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Vido, K. Articles by Gaudu, P. Search for Related Content PubMed PubMed Citation Articles by Vido, K. Articles by Gaudu, P.

Roles of Thioredoxin Reductase during the Aerobic Life of Lactococcus lactis

Unité de Recherches Laitières et Génétique Appliquée, INRA, Domaine de Vilvert, Jouy en Josas,¹ Laboratoire de Spectrométrie de Masse Bio-Organique, CNRS UMR 7509, ECPM, Université Louis Pasteur de Strasbourg, Strasbourg, France²

Received 27 July 2004/ Accepted 24 September 2004

Thiol-disulfide bond balance is generally maintained in bacteria by thioredoxin reductase-thioredoxin and/or glutathione-glutaredoxin systems. Some gram-positive bacteria, including Lactococcus lactis, do not produce glutathione, and the thioredoxin system is presumed to be essential. We constructed an L. lactis trxB1 mutant. The mutant was obtained under anaerobic conditions in the presence of dithiothreitol (DTT). Unexpectedly, the trxB1 mutant was viable without DTT and under aerated static conditions, thus disproving the essentiality of this system. Aerobic growth of the trxB1 mutant did not require glutathione, also ruling out the need for this redox maintenance system. Proteomic analyses showed that known oxidative stress defense proteins are induced in the trxB1 mutant. Two additional effects of trxB1 were not previously reported in other bacteria: (i) induction of proteins involved in fatty acid or menaquinone biosynthesis, indicating that membrane synthesis is part of the cellular response to a redox imbalance, and (ii) alteration of the isoforms of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GapB). We determined that the two GapB isoforms in L. lactis differed by the oxidation state of catalytic-site cysteine C₁₅₂. Unexpectedly, a decrease specific to the oxidized, inactive form was observed in the trxB1 mutant, possibly because of proteolysis of oxidized GapB. This study showed that thioredoxin reductase is not essential in L. lactis and that its inactivation triggers induction of several mechanisms acting at the membrane and metabolic levels. The existence of a novel redox function that compensates for trxB1 deficiency is suggested.

This article has been cited by other articles:

• Rocha, E. R., Tzianabos, A. O., Smith, C. J. (2007). Thioredoxin Reductase Is Essential for Thiol/Disulfide Redox Control and Oxidative Stress Survival of the Anaerobe Bacteroides fragilis. J. Bacteriol. 189: 8015-8023 [Abstract] [Full Text]  
• Sanchez, B., Champomier-Verges, M.-C., Stuer-Lauridsen, B., Ruas-Madiedo, P., Anglade, P., Baraige, F., de los Reyes-Gavilan, C. G., Johansen, E., Zagorec, M., Margolles, A. (2007). Adaptation and Response of Bifidobacterium animalis subsp. lactis to Bile: a Proteomic and Physiological Approach. Appl. Environ. Microbiol. 73: 6757-6767 [Abstract] [Full Text]  
• Turner, M. S., Tan, Y. P., Giffard, P. M. (2007). Inactivation of an Iron Transporter in Lactococcus lactis Results in Resistance to Tellurite and Oxidative Stress. Appl. Environ. Microbiol. 73: 6144-6149 [Abstract] [Full Text]  
• Jansch, A., Korakli, M., Vogel, R. F., Ganzle, M. G. (2007). Glutathione Reductase from Lactobacillus sanfranciscensis DSM20451T: Contribution to Oxygen Tolerance and Thiol Exchange Reactions in Wheat Sourdoughs. Appl. Environ. Microbiol. 73: 4469-4476 [Abstract] [Full Text]  
• Fu, R.-Y., Chen, J., Li, Y. (2005). Heterologous Leaky Production of Transglutaminase in Lactococcus lactis Significantly Enhances the Growth Performance of the Host. Appl. Environ. Microbiol. 71: 8911-8919 [Abstract] [Full Text]