POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
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<strong>BLAST</strong> X ______ Poster #5<br />
DYNAMICS OF THE FLAGELLAR MOTOR PROTEIN FliM<br />
Nicolas J. Delalez<br />
Microbiology Unit, Biochemistry Dept, <strong>University</strong> <strong>of</strong> Oxford, South Parks Road, Oxford OX1<br />
3QU, UK<br />
Escherichia coli swims by rotating 4-6 long helical filaments to propel the cell through its<br />
environment. The flagellar motor that rotates the filament is bidirectional and composed <strong>of</strong> two<br />
parts: the rotor and the stator, the stator being the fixed component against which the rotor<br />
spins. The stator is composed <strong>of</strong> units <strong>of</strong> two integral membrane proteins, MotA and MotB, the<br />
stoichiometry <strong>of</strong> each unit being (MotA4:MotB2). The rotor is composed <strong>of</strong> multiple rings,<br />
including the C-ring which is localized at the base <strong>of</strong> the motor and is the switch complex that<br />
gives the bidirectionality to the E. coli motor. The C-ring comprises FliG (~ 25 copies), FliM (~34<br />
copies) and FliN (> 100 copies).<br />
By using a TIRF microscope, and expressing GFP-MotB from the genome <strong>of</strong> E. coli in<br />
place <strong>of</strong> the wild-type gene, it has recently been possible to monitor the protein stoichiometry,<br />
dynamics and turnover <strong>of</strong> this stator component with single-molecule precision in functioning<br />
bacterial flagellar motors. Repeating these experiments with different flagellar motor proteins will<br />
greatly enhance our understanding <strong>of</strong> the mechanism <strong>of</strong> this motor.<br />
In particular, one <strong>of</strong> the main questions for our understanding is the mechanism <strong>of</strong> the<br />
switching process. The C-terminus <strong>of</strong> FliM, a component <strong>of</strong> the C-ring, has therefore been<br />
tagged with Ypet and expressed from the genome. Data will be presented on the construction <strong>of</strong><br />
this mutant as well as data on its dynamics, turnover and stoichoimetry, and the influence <strong>of</strong> the<br />
response regulator CheY on these features. The consequences <strong>of</strong> these results and future work<br />
will be discussed.<br />
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