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 Google Scholar
Google Scholar
Right arrow Articles by Gurvitz, A.
Right arrow Articles by Kastaniotis, A. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gurvitz, A.
Right arrow Articles by Kastaniotis, A. J.

 Previous Article  |  Next Article 

Journal of Bacteriology, April 2009, p. 2683-2690, Vol. 191, No. 8
0021-9193/09/$08.00+0     doi:10.1128/JB.01046-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Heterologous Expression of Mycobacterial Proteins in Saccharomyces cerevisiae Reveals Two Physiologically Functional 3-Hydroxyacyl-Thioester Dehydratases, HtdX and HtdY, in Addition to HadABC and HtdZ{triangledown}

Aner Gurvitz,1,2* J. Kalervo Hiltunen,2 and Alexander J. Kastaniotis2

Section of Physiology of Lipid Metabolism, Institute of Physiology, Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria,1 Department of Biochemistry and Biocenter Oulu, University of Oulu, Oulu, Finland2

Received 28 July 2008/ Accepted 6 January 2009

We report on Mycobacterium tuberculosis Rv0241c and Rv3389c, representing two physiologically functional 3-hydroxyacyl-thioester dehydratases (Htd). These enzymes are potentially entrained in type 2 fatty acid synthase (FASII). Mycobacterial FASII is involved in the synthesis of mycolic acids, which are the major constituents of the protective layer around the pathogen, shielding it from noxious chemicals and the host's immune system. Mycolic acids are additionally associated with the virulence and resilience of M. tuberculosis. Here, Rv0241c and Rv3389c, which are distinct from the previously identified heterodimers Rv0635-Rv0636 (HadAB) and Rv0636-Rv0637 (HadBC) but also the homodimer Rv0130 (HtdZ), were identified by expressing the corresponding candidate open reading frames in Saccharomyces cerevisiae htd2{Delta} cells lacking mitochondrial 3-hydroxyacyl-acyl carrier protein dehydratase activity, followed by scoring for phenotype rescue. The htd2{Delta} mutant fails to produce sufficient levels of lipoic acid and does not respire or grow on nonfermentable carbon sources. Soluble protein extracts made from mutant htd2{Delta} cells expressing mitochondrially targeted Rv0241c or Rv3389c contained 3-hydroxyacyl-thioester hydratase activity. Moreover, mutant yeast cells expressing Rv0241c or Rv3389c were able to recover their respiratory growth on glycerol medium and efficiently reduce 2,3,5-triphenyltetrazolium chloride. Additionally, expression of mitochondrial Rv0241c or Rv3389c in htd2{Delta} cells also restored de novo lipoic acid synthesis to 92 and 40% of the level in the wild-type strain, respectively. We propose naming Rv0241c and Rv3389c as HtdX and HtdY, respectively, and discuss the implications of our finding with reference to Rv0098, a candidate mycobacterial FabZ homologue with intrinsic thioesterase and hydratase activities that lacks the eukaryotic-like hydratase-2 motif.

* Corresponding author. Mailing address: Section of Physiology of Lipid Metabolism, Institute of Physiology, Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria. Phone: (43) 1 4277 62126. Fax: (43) 1 4277 62198. E-mail: aner.gurvitz{at}meduniwien.ac.at

{triangledown} Published ahead of print on 9 January 2009.

Journal of Bacteriology, April 2009, p. 2683-2690, Vol. 191, No. 8
0021-9193/09/$08.00+0     doi:10.1128/JB.01046-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





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