Document Detail

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.
MedLine Citation:
PMID:  19136596     Owner:  NLM     Status:  MEDLINE    
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 htd2Delta cells lacking mitochondrial 3-hydroxyacyl-acyl carrier protein dehydratase activity, followed by scoring for phenotype rescue. The htd2Delta 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 htd2Delta 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 htd2Delta 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.
Aner Gurvitz; J Kalervo Hiltunen; Alexander J Kastaniotis
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-01-09
Journal Detail:
Title:  Journal of bacteriology     Volume:  191     ISSN:  1098-5530     ISO Abbreviation:  J. Bacteriol.     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-04-01     Completed Date:  2009-04-23     Revised Date:  2011-04-06    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2683-90     Citation Subset:  IM    
Section of Physiology of Lipid Metabolism, Institute of Physiology, Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria.
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MeSH Terms
Bacterial Proteins / genetics,  metabolism*
Cloning, Molecular
Gene Deletion
Gene Expression
Genetic Complementation Test
Glycerol / metabolism
Hydro-Lyases / genetics,  metabolism*
Mitochondrial Proteins
Mycobacterium tuberculosis / enzymology*,  genetics
Recombinant Proteins / genetics,  metabolism
Saccharomyces cerevisiae / enzymology*,  genetics,  growth & development,  metabolism
Saccharomyces cerevisiae Proteins / genetics
Tetrazolium Salts / metabolism
Thioctic Acid / biosynthesis
Grant Support
P 19378-B03//Austrian Science Fund FWF; P 19399-B03//Austrian Science Fund FWF
Reg. No./Substance:
0/Bacterial Proteins; 0/Mitochondrial Proteins; 0/Recombinant Proteins; 0/Saccharomyces cerevisiae Proteins; 0/Tetrazolium Salts; 56-81-5/Glycerol; 62-46-4/Thioctic Acid; 902-00-1/triphenyltetrazolium; EC 4.2.1.-/Htd2 protein, S cerevisiae; EC 4.2.1.-/Hydro-Lyases

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