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 Levin, I.
Right arrow Articles by Palfey, B. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Levin, I.
Right arrow Articles by Palfey, B. A.

 Previous Article  |  Next Article 

Journal of Bacteriology, June 2007, p. 4062-4069, Vol. 189, No. 11
0021-9193/07/$08.00+0     doi:10.1128/JB.01878-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Characterization of a Novel Bifunctional Dihydropteroate Synthase/Dihydropteroate Reductase Enzyme from Helicobacter pylori{triangledown}

Itay Levin,1 Moshe Mevarech,1* and Bruce A. Palfey2

Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel,1 Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-06062

Received 13 December 2006/ Accepted 25 March 2007

Tetrahydrofolate is a ubiquitous C1 carrier in many biosynthetic pathways in bacteria, importantly, in the biosynthesis of formylmethionyl tRNAfMet, which is essential for the initiation of translation. The final step in the biosynthesis of tetrahydrofolate is carried out by the enzyme dihydrofolate reductase (DHFR). A search of the complete genome sequence of Helicobacter pylori failed to reveal any sequence that encodes DHFR. Previous studies demonstrated that the H. pylori dihydropteroate synthase gene folP can complement an Escherichia coli strain in which folA and folM, encoding two distinct DHFRs, are deleted. It was also shown that H. pylori FolP possesses an additional N-terminal domain that binds flavin mononucleotide (FMN). Homologous domains are found in FolP proteins of other microorganisms that do not possess DHFR. In this study, we demonstrated that H. pylori FolP is also a dihydropteroate reductase that derives its reducing power from soluble flavins, reduced FMN and reduced flavin adenine dinucleotide. We also determined the stoichiometry of the enzyme-bound flavin and showed that half of the bound flavin is exchangeable with the soluble flavins. Finally, site-directed mutagenesis of the most conserved amino acid residues in the N-terminal domain indicated the importance of these residues for the activity of the enzyme as a dihydropteroate reductase.

* Corresponding author. Mailing address: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel. Phone: 972-3-6408715. Fax: 972-3-6409407. E-mail: mevarech{at}post.tau.ac.il

{triangledown} Published ahead of print on 6 April 2007.

Journal of Bacteriology, June 2007, p. 4062-4069, Vol. 189, No. 11
0021-9193/07/$08.00+0     doi:10.1128/JB.01878-06
Copyright © 2007, 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»