ジャーナル: J Mol Biol / 年: 2007 タイトル: Structural model of human endoglin, a transmembrane receptor responsible for hereditary hemorrhagic telangiectasia. 著者: Oscar Llorca / Arturo Trujillo / Francisco J Blanco / Carmelo Bernabeu / 要旨: Endoglin is a type I membrane protein expressed as a disulphide-linked homodimer on human vascular endothelial cells whose haploinsufficiency is responsible for the dominant vascular dysplasia known ...Endoglin is a type I membrane protein expressed as a disulphide-linked homodimer on human vascular endothelial cells whose haploinsufficiency is responsible for the dominant vascular dysplasia known as hereditary hemorrhagic telangiectasia (HHT). Structurally, endoglin belongs to the zona pellucida (ZP) family of proteins that share a ZP domain of approximately 260 amino acid residues at their extracellular region. Endoglin is a component of the TGF-beta receptor complex, interacts with the TGF-beta signalling receptors types I and II, and modulates cellular responses to TGF-beta. Here, we have determined for the first time the three-dimensional structure of the approximately 140 kDa extracellular domain of endoglin at 25 A resolution, using single-particle electron microscopy (EM). This reconstruction provides the general architecture of endoglin, which arranges as a dome made of antiparallel oriented monomers enclosing a cavity at one end. A high-resolution structure of endoglin has also been modelled de novo and found to be consistent with the experimental reconstruction. Each subunit comprises three well-defined domains, two of them corresponding to ZP regions, organised into an open U-shaped monomer. This domain arrangement was found to closely resemble the overall structure derived experimentally and the three modelled de novo domains were tentatively assigned to the domains observed in the EM reconstruction. This molecular model was further tested by tagging endoglin's C terminus with an IgG Fc fragment visible after 3D reconstruction of the labelled protein. Combined, these data provide the structural framework to interpret endoglin's functional domains and mutations found in HHT patients.
全体 : Extracellular region of human endoglin (Glu26-Gly586), tagged wit...
全体
名称: Extracellular region of human endoglin (Glu26-Gly586), tagged with an HA epitope in N-ter and a Fc fragment in C-ter.
要素
試料: Extracellular region of human endoglin (Glu26-Gly586), tagged with an HA epitope in N-ter and a Fc fragment in C-ter.
タンパク質・ペプチド: Chimeric receptor
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超分子 #1000: Extracellular region of human endoglin (Glu26-Gly586), tagged wit...
超分子
名称: Extracellular region of human endoglin (Glu26-Gly586), tagged with an HA epitope in N-ter and a Fc fragment in C-ter. タイプ: sample / ID: 1000 / 集合状態: One homodimer / Number unique components: 1
タイプ: NEGATIVE 詳細: EndoEC-Fc was applied to carbon-coated grids and negatively stained with 1% w/v uranyl acetate.
グリッド
詳細: 40 mesh Copper/Palladium grid.
凍結
凍結剤: NONE / 装置: OTHER
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電子顕微鏡法
顕微鏡
JEOL 1230
アライメント法
Legacy - 非点収差: Correction with FFT and CCD camera
詳細
Microscope used JEOL-1230
撮影
カテゴリ: FILM / フィルム・検出器のモデル: KODAK SO-163 FILM / デジタル化 - スキャナー: OTHER / デジタル化 - サンプリング間隔: 10.5 µm 詳細: Images scanned with a MINOLTA Dimage Scan Multi Pro scanner at 2400 dpi ビット/ピクセル: 16
電子線
加速電圧: 100 kV / 電子線源: TUNGSTEN HAIRPIN
電子光学系
照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD / Cs: 2.9 mm / 倍率(公称値): 50000
試料ステージ
試料ホルダー: Eucentric / 試料ホルダーモデル: OTHER
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画像解析
最終 再構成
想定した対称性 - 点群: C2 (2回回転対称) / アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 30.0 Å / 解像度の算出法: FSC 0.5 CUT-OFF / ソフトウェア - 名称: EMAN / 使用した粒子像数: 5741