- EMDB-1658: Solution structure and characterisation of the human pyruvate deh... -
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基本情報
登録情報
データベース: EMDB / ID: EMD-1658
タイトル
Solution structure and characterisation of the human pyruvate dehydrogenase complex core assembly
マップデータ
This is a reconstruction of pyruvate dehydrogenase enzyme complex components E2 and E3BP. This contour level will display the map core, lower contour levels reveal more disordered extensions.
ジャーナル: J Mol Biol / 年: 2010 タイトル: Solution structure and characterisation of the human pyruvate dehydrogenase complex core assembly. 著者: S Vijayakrishnan / S M Kelly / R J C Gilbert / P Callow / D Bhella / T Forsyth / J G Lindsay / O Byron / 要旨: Mammalian pyruvate dehydrogenase complex (PDC) is a key multi-enzyme assembly that is responsible for glucose homeostasis maintenance and conversion of pyruvate into acetyl-CoA. It comprises a ...Mammalian pyruvate dehydrogenase complex (PDC) is a key multi-enzyme assembly that is responsible for glucose homeostasis maintenance and conversion of pyruvate into acetyl-CoA. It comprises a central pentagonal dodecahedral core consisting of two subunit types (E2 and E3BP) to which peripheral enzymes (E1 and E3) bind tightly but non-covalently. Currently, there are two conflicting models of PDC (E2+E3BP) core organisation: the 'addition' model (60+12) and the 'substitution' model (48+12). Here we present the first ever low-resolution structures of human recombinant full-length PDC core (rE2/E3BP), truncated PDC core (tE2/E3BP) and native bovine heart PDC core (bE2/E3BP) obtained by small-angle X-ray scattering and small-angle neutron scattering. These structures, corroborated by negative-stain and cryo electron microscopy data, clearly reveal open pentagonal core faces, favouring the 'substitution' model of core organisation. The native and recombinant core structures are all similar to the truncated bacterial E2 core crystal structure obtained previously. Cryo-electron microscopy reconstructions of rE2/E3BP and rE2/E3BP:E3 directly confirm that the core has open pentagonal faces, agree with scattering-derived models and show density extending outwards from their surfaces, which is much more structurally ordered in the presence of E3. Additionally, analytical ultracentrifugation characterisation of rE2/E3BP, rE2 (full-length recombinant E2-only) and tE2/E3BP supports the substitution model. Superimposition of the small-angle neutron scattering tE2/E3BP and truncated bacterial E2 crystal structures demonstrates conservation of the overall pentagonal dodecahedral morphology, despite evolutionary diversity. In addition, unfolding studies using circular dichroism and tryptophan fluorescence spectroscopy show that the rE2/E3BP is less stable than its rE2 counterpart, indicative of a role for E3BP in core destabilisation. The architectural complexity and lower stability of the E2/E3BP core may be of benefit to mammals, where sophisticated fine-tuning is required for cores with optimal catalytic and regulatory efficiencies.
ダウンロード / ファイル: emd_1658.map.gz / 形式: CCP4 / 大きさ: 7.8 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
This is a reconstruction of pyruvate dehydrogenase enzyme complex components E2 and E3BP. This contour level will display the map core, lower contour levels reveal more disordered extensions.
名称: Pyruvate dehydrogenase E2-E3BP complex / タイプ: sample / ID: 1000 集合状態: A dodecahedral lattice formed of mixed trimers of E2 and E3BP, most likely each containing 2 E2 and 1 E3BP Number unique components: 2
pH: 7.5 詳細: 2 mM EDTA, 0.01% (w/v) NaN3, 100 mM NaCl, 50 mM KH2PO4, pH 7.5
グリッド
詳細: 300 mesh copper grid with lacey carbon film
凍結
凍結剤: ETHANE / チャンバー内温度: 100 K / 装置: HOMEMADE PLUNGER / 詳細: Vitrification instrument: Homemade plunger 手法: Blot briefly before plunging, using Wahtman no.1 paper
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電子顕微鏡法
顕微鏡
FEI TECNAI F30
温度
平均: 115 K
アライメント法
Legacy - 非点収差: At 200,000 magnification
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: ZEISS SCAI / デジタル化 - サンプリング間隔: 7 µm / 実像数: 16 詳細: Images were binned from a scanned pixel size at the specimen of 1.8A to 3.6A using Proc2D Od range: 5 / ビット/ピクセル: 8
想定した対称性 - 点群: I (正20面体型対称) / アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 18.3 Å / 解像度の算出法: FSC 0.5 CUT-OFF / ソフトウェア - 名称: Spider, WellMAP 詳細: Final map had converged to given resolution, on a 1 degree spacing. 使用した粒子像数: 982
Chain - #0 - Chain ID: A / Chain - #1 - Chain ID: B / Chain - #2 - Chain ID: C / Chain - #3 - Chain ID: D / Chain - #4 - Chain ID: E
ソフトウェア
名称: Chimera
詳細
PDBEntryID_givenInChain. Protocol: Rigid body, after icosahedral symmetrization. The icosahedral assembly was constructed and then fitted as a rigid body.
精密化
空間: REAL / プロトコル: RIGID BODY FIT / 当てはまり具合の基準: CCC