POSTERS - BLAST X - University of Utah

BLAST X Poster #25
ATTEMPT TO PURIFY THE HOOK-BASAL BODY WITH C-RING FROM THE Na + -DRIVEN
FLAGELLAR MOTOR
Masafumi Koike, Seiji Kojima, Michio Homma
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku,
Nagoya 464-8602, Japan.
The flagellum is the biggest architecture in the bacterial organ. At the base of each
flagellum, there is a rotary motor embedded in the membrane whose energy source is the
electrochemical gradient of the specific ion across the membrane. E. coli and Salmonella have
the H + driven motor, and Vibrio alginolyticus has Na + driven type. The motor is composed of the
rotor and the stator, and torque is generated by the interactions between them. The hook-basal
body (HBB) is the rotor part of the motor composed of rod, LP-, MS-ring and hook. C-ring is
mounted on the cytoplasmic side of the MS-ring of HBB, and believed to be involved in torque
generation in rotor side of the motor. It is composed of three proteins; FliM, FliN, and FliG. FliG
is the most closely participated in the torque generation among them. To elucidate the
mechanism of torque generation, we undertake the isolation of C-ring from the Na + -driven polar
flagellum of V. alginolyticus to investigate rotor-stator interactions. We applied the C-ring
isolation method established for Salmonella, but that resulted in the HBB without C-ring. It
indicates that solubilization by Triton X-100 was harsh for C-ring of Vibrio. Suitable detergents
were screened and we found that CHAPS could solubilize HBB with FliG attached. Currently
immunoelectron microscopic observation is ongoing to directly detect FliG attached on the MSring.
Also, we are searching more favorable conditions to isolate remaining C-ring proteins, FliM
and FliN.
76