[ODP-053] 電子線トモグラフィーによるMycoplasma mobile内部滑走装置の構造解析
Mycoplasma mobile, a fish pathogen glides by a unique mechanism. The internal part of gliding machinery has an elliptical structure named bell with a major axis of 235±31 nm at the front side, and approximately 28 chains connected to the bell. Each chain consists of 17 dimeric motors composed of an F-type ATPase homolog. In this study, we acquired tomograms by negatively-stained transmission electron microscopy, and reconstructed the three dimensional structures for intact cells, membrane removed cells, permeabilized cells and isolated bells. Based on these structures, we suggest an integrated image as follows. The bell is a bowl composed of 30-40 nm thick wall featured by a honeycomb structure with 8.6 nm periodicity. A 8-12 nm wide band at the rim of the bowl binds the chains of dimeric motors. A part of cell membrane sometimes remains on the bell surface, even after twice of 0.1% Triton X-100 treatments, suggesting the existence of an unknown structure supporting the membrane on the bell. The chains have lateral linkers, which may be involved in cooperative behaviors of the chains.