Properties of Rhodobacter Sphaeroides Flagellar Motor Proteins
The purple non-sulphur bacterium Rhodobacter sphaeroides swims due to the rapid rotation of a single unidirectional flagellum . It is well documented that this organism makes tactic swimming responses to a variety of stimuli which include light intensity, pH, partial pressure of oxygen, and concentration gradients of a range of organic chemicals found in the aquatic environments in which they live . Rhodobacter sphaeroides swimming behaviour is produced by modulating the stopping and starting of the single, medially located flagellum. Cells reorientate to a new swimming direction when rotation stops and the flagellum coils up. Most work in bacterial motility has been carried out in enteric species Salmonella typhimurium and Escherichia coli which possess between five and eight flagella . Swimming behaviour is modulated by “switching”the direction of flagellar rotation (counterclockwise rotation results in cells swimming vectorially i.e “running”and clockwise rotation causes the cells to “tumble”until a favourable direction is found). Flagella that work in this manner possess motors that are termed bidirectional.
KeywordsAgar Torque Cysteine Polypeptide Photosynthesis
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- 1.Armitage, J.P., Kelly, D.J. & Sockett, R.E. (1995) Flagellate motility, behavioural respnses and active transport in purple non-sulfur bacteria. In Advances in Photosynthesis, volume 2, R.E. Blankenship, M.T. Madigan, & C.E. Bauer (eds.), Anoxygenic Photosynthetic Bacteria, pp 1005–1028. Kluwer Academic Publishers, Dordrecht.Google Scholar
- 3.Sockett, R.E., Foster, J.C.A. and Armitage, J.P. (1990) Molecular biology of the Rhodobacter sphaeroides flagellum. FEMS Symp. 53, 473–479.Google Scholar
- 4.Sockett, R.E. and Armitage, J.P. (1991) Isolation, characterization and complementation of a paralysed flagellar mutant of Rhodobacter sphaeroides WS8. J. Bacteriol. 173, 2786–2790.Google Scholar
- 9.Oosawa K., Ueno, T. and Aizawa, S.-I. (1994) Overproduction of the bacterial flagellar switch proteins and their interactions with the MS ring complex in vitro. J. Bacteriol 175. 6041–6045.Google Scholar