ジャーナル: Nat Struct Mol Biol / 年: 2015 タイトル: Atomic structures of a bactericidal contractile nanotube in its pre- and postcontraction states. 著者: Peng Ge / Dean Scholl / Petr G Leiman / Xuekui Yu / Jeff F Miller / Z Hong Zhou / 要旨: R-type pyocins are representatives of contractile ejection systems, a class of biological nanomachines that includes, among others, the bacterial type VI secretion system (T6SS) and contractile ...R-type pyocins are representatives of contractile ejection systems, a class of biological nanomachines that includes, among others, the bacterial type VI secretion system (T6SS) and contractile bacteriophage tails. We report atomic models of the Pseudomonas aeruginosa precontraction pyocin sheath and tube, and the postcontraction sheath, obtained by cryo-EM at 3.5-Å and 3.9-Å resolutions, respectively. The central channel of the tube is negatively charged, in contrast to the neutral and positive counterparts in T6SSs and phage tails. The sheath is interwoven by long N- and C-terminal extension arms emanating from each subunit, which create an extensive two-dimensional mesh that has the same connectivity in the extended and contracted state of the sheath. We propose that the contraction process draws energy from electrostatic and shape complementarities to insert the inner tube through bacterial cell membranes to eventually kill the bacteria.
装置: FEI VITROBOT MARK IV / 凍結剤: ETHANE / Temp: 90 K / 湿度: 100 % 詳細: Blot for 4 seconds (blot force 1) before plunging into liquid ethane (FEI VITROBOT MARK IV). 手法: Blot time 4 seconds, blot force 1
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電子顕微鏡撮影
実験機器
モデル: Titan Krios / 画像提供: FEI Company
顕微鏡
モデル: FEI TITAN KRIOS / 日付: 2009年10月7日 / 詳細: Scanned with 9200 ED