ジャーナル: J Mol Biol / 年: 2012 タイトル: Filaments from Ignicoccus hospitalis show diversity of packing in proteins containing N-terminal type IV pilin helices. 著者: Xiong Yu / Charles Goforth / Carolin Meyer / Reinhard Rachel / Reinhard Wirth / Gunnar F Schröder / Edward H Egelman / 要旨: Bacterial motility is driven by the rotation of flagellar filaments that supercoil. The supercoiling involves the switching of coiled-coil protofilaments between two different states. In archaea, the ...Bacterial motility is driven by the rotation of flagellar filaments that supercoil. The supercoiling involves the switching of coiled-coil protofilaments between two different states. In archaea, the flagellar filaments responsible for motility are formed by proteins with distinct homology in their N-terminal portion to bacterial Type IV pilins. The bacterial pilins have a single N-terminal hydrophobic α-helix, not the coiled coil found in flagellin. We have used electron cryo-microscopy to study the adhesion filaments from the archaeon Ignicoccus hospitalis. While I. hospitalis is non-motile, these filaments make transitions between rigid stretches and curved regions and appear morphologically similar to true archaeal flagellar filaments. A resolution of ~7.5Å allows us to unambiguously build a model for the packing of these N-terminal α-helices, and this packing is different from several bacterial Type IV pili whose structure has been analyzed by electron microscopy and modeling. Our results show that the mechanism responsible for the supercoiling of bacterial flagellar filaments cannot apply to archaeal filaments.
想定した対称性 - らせんパラメータ - Δz: 5.3 Å 想定した対称性 - らせんパラメータ - ΔΦ: 106.65 ° アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 7.5 Å / 解像度の算出法: OTHER / ソフトウェア - 名称: Spider, IHRSR 詳細: Each image was multiplied by the CTF. The final volume was amplitude-corrected in Fourier space by dividing by the sum of the squared CTFs.