This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
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 HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Paul, K.
Right arrow Articles by Blair, D. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Paul, K.
Right arrow Articles by Blair, D. F.

 Previous Article  |  Next Article 

Journal of Bacteriology, April 2006, p. 2502-2511, Vol. 188, No. 7
0021-9193/06/$08.00+0     doi:10.1128/JB.188.7.2502-2511.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Organization of FliN Subunits in the Flagellar Motor of Escherichia coli{dagger}

Koushik Paul and David F. Blair*

Department of Biology, University of Utah, Salt Lake City, Utah 84112

Received 21 December 2005/ Accepted 10 January 2006

FliN is a major constituent of the C ring in the flagellar basal body of many bacteria. It is present in >100 copies per flagellum and together with FliM and FliG forms the switch complex that functions in flagellar assembly, rotation, and clockwise-counterclockwise switching. FliN is essential for flagellar assembly and switching, but its precise functions are unknown. The C-terminal part of the protein is best conserved and most important for function; a crystal structure of this C-terminal domain of FliN from Thermotoga maritima revealed a saddle-shaped dimer formed mainly from ß strands (P. N. Brown, M. A. A. Mathews, L. A. Joss, C. P. Hill, and D. F. Blair, J. Bacteriol. 187:2890-2902, 2005). Equilibrium sedimentation studies showed that FliN can form stable tetramers and that a FliM1FliN4 complex is also stable. Here, we have examined the organization of FliN subunits by using targeted cross-linking. Cys residues were introduced at various positions in FliN, singly or in pairs, and disulfide cross-linking was induced by oxidation. Efficient cross-linking was observed for certain positions near the ends of the dimer and for some positions in the structurally uncharacterized N-terminal domain. Certain combinations of two Cys replacements gave a high yield of cross-linked tetramer. The results support a model in which FliN is organized in doughnut-shaped tetramers, stabilized in part by contacts involving the N-terminal domain. Electron microscopic reconstructions show a bulge at the bottom of the C-ring whose size and shape are a close match for the hypothesized FliN tetramer.

* Corresponding author. Mailing address: Department of Biology, University of Utah, Salt Lake City, UT 84112. Phone: (801) 585-3709. Fax: (801) 581-4668. E-mail: blair{at}bioscience.utah.edu.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

Journal of Bacteriology, April 2006, p. 2502-2511, Vol. 188, No. 7
0021-9193/06/$08.00+0     doi:10.1128/JB.188.7.2502-2511.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Kojima, S., Furukawa, Y., Matsunami, H., Minamino, T., Namba, K. (2008). Characterization of the Periplasmic Domain of MotB and Implications for Its Role in the Stator Assembly of the Bacterial Flagellar Motor. J. Bacteriol. 190: 3314-3322 [Abstract] [Full Text]  
  • Brown, P. N., Terrazas, M., Paul, K., Blair, D. F. (2007). Mutational Analysis of the Flagellar Protein FliG: Sites of Interaction with FliM and Implications for Organization of the Switch Complex. J. Bacteriol. 189: 305-312 [Abstract] [Full Text]  
  • Manson, M. D. (2007). How 34 Pegs Fit into 26 + 8 Holes in the Flagellar Motor. J. Bacteriol. 189: 291-293 [Full Text]  
  • Thomas, D. R., Francis, N. R., Xu, C., DeRosier, D. J. (2006). The Three-Dimensional Structure of the Flagellar Rotor from a Clockwise-Locked Mutant of Salmonella enterica Serovar Typhimurium.. J. Bacteriol. 188: 7039-7048 [Abstract] [Full Text]  
  • Park, S.-Y., Lowder, B., Bilwes, A. M., Blair, D. F., Crane, B. R. (2006). Structure of FliM provides insight into assembly of the switch complex in the bacterial flagella motor. Proc. Natl. Acad. Sci. USA 103: 11886-11891 [Abstract] [Full Text]  
  • Paul, K., Harmon, J. G., Blair, D. F. (2006). Mutational Analysis of the Flagellar Rotor Protein FliN: Identification of Surfaces Important for Flagellar Assembly and Switching.. J. Bacteriol. 188: 5240-5248 [Abstract] [Full Text]  


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