+データを開く
-基本情報
登録情報 | データベース: EMDB / ID: EMD-3904 | |||||||||
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タイトル | CryoEM density map of the pseudosymmetric PLC editing modules | |||||||||
マップデータ | Cryo-EM density of a protein complex | |||||||||
試料 |
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生物種 | Homo sapiens (ヒト) | |||||||||
手法 | 単粒子再構成法 / クライオ電子顕微鏡法 / 解像度: 7.2 Å | |||||||||
データ登録者 | Januliene D / Blees A / Trowitzsch S / Tampe R / Moeller A | |||||||||
引用 | ジャーナル: Nature / 年: 2017 タイトル: Structure of the human MHC-I peptide-loading complex. 著者: Andreas Blees / Dovile Januliene / Tommy Hofmann / Nicole Koller / Carla Schmidt / Simon Trowitzsch / Arne Moeller / Robert Tampé / 要旨: The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates ...The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates peptide translocation into the endoplasmic reticulum with loading and editing of major histocompatibility complex class I (MHC-I) molecules. After final proofreading in the PLC, stable peptide-MHC-I complexes are released to the cell surface to evoke a T-cell response against infected or malignant cells. Sampling of different MHC-I allomorphs requires the precise coordination of seven different subunits in a single macromolecular assembly, including the transporter associated with antigen processing (TAP1 and TAP2, jointly referred to as TAP), the oxidoreductase ERp57, the MHC-I heterodimer, and the chaperones tapasin and calreticulin. The molecular organization of and mechanistic events that take place in the PLC are unknown owing to the heterogeneous composition and intrinsically dynamic nature of the complex. Here, we isolate human PLC from Burkitt's lymphoma cells using an engineered viral inhibitor as bait and determine the structure of native PLC by electron cryo-microscopy. Two endoplasmic reticulum-resident editing modules composed of tapasin, calreticulin, ERp57, and MHC-I are centred around TAP in a pseudo-symmetric orientation. A multivalent chaperone network within and across the editing modules establishes the proofreading function at two lateral binding platforms for MHC-I molecules. The lectin-like domain of calreticulin senses the MHC-I glycan, whereas the P domain reaches over the MHC-I peptide-binding pocket towards ERp57. This arrangement allows tapasin to facilitate peptide editing by clamping MHC-I. The translocation pathway of TAP opens out into a large endoplasmic reticulum lumenal cavity, confined by the membrane entry points of tapasin and MHC-I. Two lateral windows channel the antigenic peptides to MHC-I. Structures of PLC captured at distinct assembly states provide mechanistic insight into the recruitment and release of MHC-I. Our work defines the molecular symbiosis of an ABC transporter and an endoplasmic reticulum chaperone network in MHC-I assembly and provides insight into the onset of the adaptive immune response. | |||||||||
履歴 |
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-構造の表示
ムービー |
ムービービューア |
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構造ビューア | EMマップ: SurfViewMolmilJmol/JSmol |
添付画像 |
-ダウンロードとリンク
-EMDBアーカイブ
マップデータ | emd_3904.map.gz | 26.4 MB | EMDBマップデータ形式 | |
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ヘッダ (付随情報) | emd-3904-v30.xml emd-3904.xml | 9.3 KB 9.3 KB | 表示 表示 | EMDBヘッダ |
画像 | emd_3904.png | 36.2 KB | ||
アーカイブディレクトリ | http://ftp.pdbj.org/pub/emdb/structures/EMD-3904 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-3904 | HTTPS FTP |
-関連構造データ
-リンク
EMDBのページ | EMDB (EBI/PDBe) / EMDataResource |
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-マップ
ファイル | ダウンロード / ファイル: emd_3904.map.gz / 形式: CCP4 / 大きさ: 30.5 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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注釈 | Cryo-EM density of a protein complex | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ボクセルのサイズ | X=Y=Z: 1.077 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
密度 |
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対称性 | 空間群: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
詳細 | EMDB XML:
CCP4マップ ヘッダ情報:
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-添付データ
-試料の構成要素
-全体 : Protein complex
全体 | 名称: Protein complexタンパク質複合体 |
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要素 |
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-超分子 #1: Protein complex
超分子 | 名称: Protein complex / タイプ: complex / ID: 1 / 親要素: 0 |
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由来(天然) | 生物種: Homo sapiens (ヒト) |
-実験情報
-構造解析
手法 | クライオ電子顕微鏡法 |
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解析 | 単粒子再構成法 |
試料の集合状態 | particle |
-試料調製
濃度 | 2 mg/mL |
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緩衝液 | pH: 7.5 |
グリッド | モデル: C-flat-2/2 |
凍結 | 凍結剤: ETHANE / チャンバー内湿度: 100 % |
-電子顕微鏡法
顕微鏡 | FEI TITAN KRIOS |
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電子線 | 加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN |
電子光学系 | 照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELDBright-field microscopy |
撮影 | フィルム・検出器のモデル: GATAN K2 QUANTUM (4k x 4k) 検出モード: COUNTING / 平均電子線量: 55.0 e/Å2 |
実験機器 | モデル: Titan Krios / 画像提供: FEI Company |
-画像解析
CTF補正 | ソフトウェア - 名称: Gctf 詳細: CTF correction was performed internally in Relion and Frealign |
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初期モデル | モデルのタイプ: OTHER 詳細: Selected particles from best 2D class averages were subjected to 3D-classification in Relion, using a low-pass filtered global average as a starting model. The best map was then used as an ...詳細: Selected particles from best 2D class averages were subjected to 3D-classification in Relion, using a low-pass filtered global average as a starting model. The best map was then used as an initial model for subsequent 3D classification |
初期 角度割当 | タイプ: ANGULAR RECONSTITUTION / ソフトウェア - 名称: RELION |
最終 角度割当 | タイプ: ANGULAR RECONSTITUTION |
最終 再構成 | 想定した対称性 - 点群: C1 (非対称) / アルゴリズム: FOURIER SPACE / 解像度のタイプ: BY AUTHOR / 解像度: 7.2 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: FREALIGN (ver. X) / 使用した粒子像数: 22915 |