This Article Full Text (PDF) Other Versions of this Article: JB.00451-06v1 189/5/1803    most recent 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 Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Stork, M. Articles by Crosa, J. H. Search for Related Content PubMed PubMed Citation Articles by Stork, M. Articles by Crosa, J. H.

 Previous Article  |  Next Article 

J. Bacteriol. doi:10.1128/JB.00451-06
Copyright (c) 2006, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

A novel protein, TtpC, is a required component of the TonB2 complex for specific iron transport in the pathogens Vibrio anguillarum and Vibrio cholerae

Department of Molecular Microbiology and Immunology L-220, Oregon Health and Science University, Portland, OR, 97239-3098.; Department of Molecular Microbiology, Institute of Molecular Cell Biology, Faculty of Earth and Life Science, Vrije Universiteit, Amsterdam, The Netherlands

^* To whom correspondence should be addressed. Email: crosajor{at}ohsu.edu.

	Abstract

Active transport across the outer membrane in Gram-negative bacteria requires the energy that is generated by the proton motive force in the inner membrane. This energy is transduced to the outer membrane by the TonB protein in complex with the proteins ExbB and ExbD. In the pathogen Vibrio anguillarum we have identified two TonB systems, TonB1 and TonB2, the latter used for ferric-anguibactin transport and is transcribed as part of an operon that consists of orf2-exbB2-exbD2-tonB2. This later cluster was identified by a polar transposon insertion in orf2 that resulted in a strain deficient for ferric-anguibactin transport. Only the entire cluster (orf2, exbB2, exbD2 and tonB2) could complement for ferric-anguibactin transport while just the exbB2-exbD2-tonB2 genes were unable to restore transport. This suggests an essential role for this Orf2, designated TtpC, in TonB2 mediated transport in V. anguillarum. A similar gene cluster exists in V. cholerae, i.e. with the homologues of ttpC-exbB2-exbD2-tonB2 and we demonstrate that TtpC from V. cholerae also plays a role in the TonB2-mediated transport of enterobactin in this human pathogen. Furthermore, we also show that in V. anguillarum the TtpC protein is found as part of a complex that might also contain the TonB2, ExbB2 and ExbD2 proteins. This novel component of the TonB2 system found in V. anguillarum and V. cholerae, is perhaps a general feature in bacteria harboring the Vibrio-like TonB2 system.