ジャーナル: J Struct Biol / 年: 2012 タイトル: Toll-like receptor 5 forms asymmetric dimers in the absence of flagellin. 著者: Kaifeng Zhou / Ryuta Kanai / Phong Lee / Hong-Wei Wang / Yorgo Modis / 要旨: The structure of full-length human TLR5 determined by electron microscopy single-particle image reconstruction at 26Å resolution shows that TLR5 forms an asymmetric homodimer via ectodomain ...The structure of full-length human TLR5 determined by electron microscopy single-particle image reconstruction at 26Å resolution shows that TLR5 forms an asymmetric homodimer via ectodomain interactions. The structure shows that like TLR9, TLR5 dimerizes in the absence of ligand. The asymmetry of the dimer suggests that TLR5 may recognize two flagellin molecules cooperatively to establish an optimal flagellin response threshold. A TLR5 homology model was generated and fitted into the electron microscopy structure. All seven predicted N-linked glycosylation sites are exposed on the molecular surface, away from the dimer interface. Glycosylation at the first five sites was confirmed by tandem mass spectrometry. Two aspartate residues proposed to interact with flagellin (Asp294 and Asp366) are sterically occluded by a glycan at position 342. In contrast, the central region of the ectodomains near the dimer interface is unobstructed by glycans. Ligand binding in this region would be consistent with the ligand binding sites of other TLRs.
生物種: Homo sapiens (ヒト) / 別称: Human / 細胞: Sf9 insect cells / Organelle: membrane / 細胞中の位置: plasma membrane
分子量
実験値: 200 KDa / 理論値: 200 KDa
組換発現
生物種: Sf9 insect cells / 組換プラスミド: pAcGP67-A
配列
InterPro: Toll-like receptor
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実験情報
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構造解析
手法
ネガティブ染色法
解析
単粒子再構成法
試料の集合状態
particle
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試料調製
濃度
0.005 mg/mL
緩衝液
pH: 7.5 / 詳細: 10 mM TEA, 0.15 M NaCl
染色
タイプ: NEGATIVE 詳細: The protein solution was applied onto a thin-carbon-covered holey carbon copper grid and negatively stained in 1% uranyl-formate solution for 1 minute.
試料ホルダー: Eucentric / 試料ホルダーモデル: SIDE ENTRY, EUCENTRIC
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画像解析
最終 再構成
アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 26.0 Å / 解像度の算出法: FSC 0.5 CUT-OFF / ソフトウェア - 名称: IMAGIC SPIDER 詳細: Final maps were calculated from all the particles by back-projection reconstruction. 使用した粒子像数: 3087