POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>BLAST</strong> X Poster #27<br />
VISUALIZATION OF EXCHANGE OF ROTOR COMPONENT IN FUNCTIONING BACTERIAL<br />
FLAGELLAR MOTOR<br />
Hajime Fukuoka, Shun Terasawa, Yuichi Inoue, Akihiko Ishijima<br />
IMRAM, Tohoku Univ., 2-1-1 Katahira, Aoba-ku, Sendai, 980-5877, Japan<br />
Bacterial flagellum is a supramolecular complex penetrating the bacterial cell envelope,<br />
including the cytoplasmic and the outer membranes. Bacterial flagellum consists <strong>of</strong> a basal body<br />
(rotary motor), a helical filament (propeller), and a hook (universal joint). The flagellar motor is<br />
driven by the electrochemical potential <strong>of</strong> H +<br />
or Na + , and the interaction between stator and a<br />
rotor <strong>of</strong> flagellar motor is thought to generate the motor rotation. Stator parts are exchanged in a<br />
functioning motor and the assembly <strong>of</strong> stator to the motor requires coupling ion for the motor<br />
rotation. In this study, we focused on protein dynamics <strong>of</strong> rotor in functioning bacterial flagellar<br />
motors. We constructed GFP-fusions <strong>of</strong> rotor components, and investigated whether rotor<br />
components are exchanged in a functioning motor by Fluorescent Recovery After<br />
Photobleaching (FRAP) experiment for a single motor.<br />
We constructed the expression systems <strong>of</strong> GFP-FliG, FliM-GFP, and GFP-FliN as GFPfusions<br />
<strong>of</strong> rotor components. In tethered cells producing each GFP-fusions, we observed the<br />
localization <strong>of</strong> fluorescent spot at the rotational center. Each GFP fusion was probably<br />
incorporated into flagellar motor as a rotor component. To observe the exchange <strong>of</strong> rotor<br />
components, we carried out FRAP experiment using evanescent illumination to the motor<br />
located at rotational center <strong>of</strong> the tethered cell. When fluorescent spot <strong>of</strong> FliM-GFP or GFP-FliN<br />
localized at rotational center was photobleached, the fluorescence at the rotational center<br />
recovered with the passage <strong>of</strong> time. On the other hand, the recovery <strong>of</strong> fluorescence was not<br />
observed in cells producing GFP-FliG. These results indicate that some rotor components, FliN<br />
and FliM at least, assemble to the motor even after the functional motor is constructed.<br />
Probably, in functioning motor, some components <strong>of</strong> flagellar structure are exchanged<br />
dynamically. We would like to clarify turnover rates <strong>of</strong> rotor components until the annual<br />
meeting.<br />
78
Change language