	School of Clinical Laboratory Sciences
Genetics

Genetics, biochemistry and physiology of bacterial flagellar function

Rhodobacter picture

Cartoon

Rhodobacter sphaeroides Showing coiled single flagellum

Dr. R.E. Sockett

Genetics, biochemistry and physiology of bacterial flagellar function

Flagella are helical propellers with rotary motors that form part of the bacterial cell membrane. Movement of ions through motor proteins results in the rotation of flagella, causing bacteria to swim, but the full mechanistic details are unknown. Swimming is common in bacterial pathogens and is also widespread across non-pathogenic bacterial genera.

We are using genetic and biochemical techniques to study the mode of action of several flagellar motor proteins. With Professor J. Armitage (Oxford University) we are testing interactions between CheY chemotaxis proteins and FliM. We are studying the interaction between the chemotaxis machinery and the flagellar motor by altering FliM and FliG proteins and studying the effect on swimming behaviour. With Dr. Ian Mellor (School of Biological Sciences) we are using electrophysiological techniques to test ion conductance properties of wild-type and "mutant" peptides derived from motor proteins. With Professors Williams and King (Schools of Pharmaceutical Sciences and Mathematics) we are assessing the role of motility in the establishment of a bacterial infection. Projects involve molecular biology, gene manipulation, biochemistry and microscopy.

Rhodobacter sphaeroides

The flagellated bacterium Rhodobacter sphaeroides is often used in our experiments.

Rho 1st.jpg (49907 bytes) Rhodobacter growth Rho 3rd.jpg (53991 bytes) Rho 4th.jpg (49866 bytes)

Rhodobacter (red bacterium) produce a complex of green, brown and red pigments when grown in light. Above is 7 days growth.

Artists impression of the flagellum inserted into the photosynthetic membrane of Rhodobacter sphaeroides, by Johnathon Soul (B.Sc. Zoology 1995)

References

Asai, Y., Kawagishi, I., Sockett, R.E. and Homma, M. (1999) A hybrid motor with H+- and Na+- driven components can rotate virbio polar flagella by using sodium ions. J. Bacteriol. 181 No. 20, p6332-6338.

Shah, D.S., Perehinec, T., Stevens, S.E., Aizawa, S.I. and Sockett, R.E. (2000) Flagellar filament of Rhodobacter sphaeroides pH induced polymorphic changes and analysis of the fliC gene. J. Bacteriol. 182 No 18, p5218-5224.

Bostock-Smith, C., Sharman, G.J., Sockett, R.E. and Searle, M. (2000) Evidence for beta sheet conformation in peptides derived from MotB from Rhodobacter sphaeroides. J. Chem Soc. Perkin Trans 2, 479-483.

Asai, Y., Kawagishi, I., Sockett, R.E. and Homma, M. (2000) Coupling ion specificity of chimeras between H- and Na- driven motor proteins, MotB and PomB, in Vibrio polar flagella. EMBO J. July 17, 2000; 19 (14) p3639-3648.

Sockett, R.E. (1998) Characterising flagella and motile behaviour. In: Bacterial Pathogenesis, Methods in Microbiology, Vol. 27. Williams, Salmond, Ketley Eds. Academic Press, U.K. p.227-237.

Sockett, R.E., Goodfellow, I.G.P., Gunther, G., Edge, M.J.E. and Shah, D.S. (1998) "Properties of Rhodobacter sphaeroides flegellar motor proteins". In The Photosynthetic Prokaryotes, Eds. G.A. Preschek, W. Loffelhardt, G. Schmetterer. Plenum Press, pp 693-698.

Page, M.D. and Sockett, R.E. (1998) Molecular genetic methods for Paracoccus and Rhodobacter with reference to studies of photosynthesis and respiration. In Methods in Microbiology Vol. 29 "Genetic Methods for Diverse Prokaryotes". Eds. M.C.M. Smith and R.E. Sockett. Academic Press 1999.

Goodfellow, I.G.P. et al. (1996) Cloning of the flil gene from R. sphaeroides WS8. FEMS 142, 111-116.

Shah, D.S. and Sockett, R.E. (1995) Analysis of the motA flagellar motor gene from Rhodobacter sphaeroides. Mol. Microbiol. 17, 961-969.

Link to Rhodobacter genome page http://www-mmg.med.uth.tmc.edu/sphaeroides/