ジャーナル: J Biol Chem / 年: 2012 タイトル: Novel actin-like filament structure from Clostridium tetani. 著者: David Popp / Akihiro Narita / Lin Jie Lee / Umesh Ghoshdastider / Bo Xue / Ramanujam Srinivasan / Mohan K Balasubramanian / Toshitsugu Tanaka / Robert C Robinson / 要旨: Eukaryotic F-actin is constructed from two protofilaments that gently wind around each other to form a helical polymer. Several bacterial actin-like proteins (Alps) are also known to form F-actin- ...Eukaryotic F-actin is constructed from two protofilaments that gently wind around each other to form a helical polymer. Several bacterial actin-like proteins (Alps) are also known to form F-actin-like helical arrangements from two protofilaments, yet with varied helical geometries. Here, we report a unique filament architecture of Alp12 from Clostridium tetani that is constructed from four protofilaments. Through fitting of an Alp12 monomer homology model into the electron microscopy data, the filament was determined to be constructed from two antiparallel strands, each composed of two parallel protofilaments. These four protofilaments form an open helical cylinder separated by a wide cleft. The molecular interactions within single protofilaments are similar to F-actin, yet interactions between protofilaments differ from those in F-actin. The filament structure and assembly and disassembly kinetics suggest Alp12 to be a dynamically unstable force-generating motor involved in segregating the pE88 plasmid, which encodes the lethal tetanus toxin, and thus a potential target for drug design. Alp12 can be repeatedly cycled between states of polymerization and dissociation, making it a novel candidate for incorporation into fuel-propelled nanobiopolymer machines.
名称: FILAMENT STRUCTURE OF AN ACTIN -LIKE PROTEIN, ALP12, IN CLOSTRIDIUM TETANI タイプ: COMPLEX
緩衝液
pH: 7.5
試料
包埋: NO / シャドウイング: NO / 染色: YES / 凍結: NO
染色
タイプ: NEGATIVE / 染色剤: uranyl acetate
試料支持
詳細: CARBON
急速凍結
詳細: NEGATIVELY STAINED
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電子顕微鏡撮影
顕微鏡
モデル: HITACHI H7600 / 日付: 2011年9月6日
電子銃
電子線源: LAB6 / 加速電圧: 100 kV / 照射モード: FLOOD BEAM
電子レンズ
モード: BRIGHT FIELD / 倍率(公称値): 40000 X / 最大 デフォーカス(公称値): 5000 nm / 最小 デフォーカス(公称値): 800 nm
撮影
フィルム・検出器のモデル: KODAK SO-163 FILM
画像スキャン
デジタル画像の数: 31
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解析
EMソフトウェア
名称: EOS / カテゴリ: 3次元再構成
CTF補正
詳細: EACH SCANNED IMAGE
3次元再構成
手法: SINGLE PARTICLE ANALYSIS / 解像度: 19.7 Å / 粒子像の数: 5582 / ピクセルサイズ(公称値): 2.68 Å / ピクセルサイズ(実測値): 2.68 Å 詳細: SINGLE PARTICLE ANALYSIS USING EOS SOFTWARE PACKAGE SUBMISSION BASED ON EXPERIMENTAL DATA FROM EMDB EMD-2068. (DEPOSITION ID: 10712). 対称性のタイプ: HELICAL
原子モデル構築
プロトコル: RIGID BODY FIT / 空間: REAL / 詳細: METHOD--RIGID BODY REFINEMENT PROTOCOL--X-RAY