Deletion analysis of the FliM flagellar switch protein of Salmonella typhimurium - PubMed (original) (raw)

Deletion analysis of the FliM flagellar switch protein of Salmonella typhimurium

A S Toker et al. J Bacteriol. 1996 Dec.

Abstract

The flagellar switch of Salmonella typhimurium and Escherichia coli is composed of three proteins, FliG, FliM, and FliN. The switch complex modulates the direction of flagellar motor rotation in response to information about the environment received through the chemotaxis signal transduction pathway. In particular, chemotaxis protein CheY is believed to bind to switch protein FliM, inducing clockwise filament rotation and tumbling. To investigate the function of FliM and its interactions with FliG and FliN, we engineered a series of 34 FliM deletion mutant proteins, each lacking a different 10-amino-acid segment. We have determined the phenotype associated with each mutant protein, the ability of each mutant protein to interfere with the motility of wild-type cells, and the effect of additional FliG and FliN on the function of selected FliM mutant proteins. Overall, deletions at the N terminus produced a counterclockwise switch bias, deletions in the central region of the protein produced poorly motile or nonflagellate cells, and deletions near the C terminus produced only nonflagellate cells. On the basis of this evidence and the results of a previous study of spontaneous FliM mutants (H. Sockett, S. Yamaguchi, M. Kihara, V. M. Irikura, and R. M. Macnab, J. Bacteriol. 174:793-806, 1992), we propose a division of the FliM protein into four functional regions: an N-terminal region primarily involved in switching, an extended N-terminal region involved in switching and assembly, a middle region involved in switching and motor rotation, and a C-terminal region primarily involved in flagellar assembly.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Biochemistry. 1992 Feb 18;31(6):1821-6 - PubMed
    1. J Bacteriol. 1992 Feb;174(3):793-806 - PubMed
    1. J Bacteriol. 1993 Feb;175(3):802-10 - PubMed
    1. Proc Natl Acad Sci U S A. 1993 Oct 1;90(19):8787-91 - PubMed
    1. J Mol Biol. 1994 Jan 28;235(4):1261-70 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources