- EMDB-5772: A Two-Pronged Structural Analysis of Retroviral Maturation Indica... -
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基本情報
登録情報
データベース: EMDB / ID: EMD-5772
タイトル
A Two-Pronged Structural Analysis of Retroviral Maturation Indicates that Core Formation Proceeds by a Disassembly-Reassembly Pathway Rather than a Displacive Transition
マップデータ
T=1 icosahedral assembly of Rous sarcoma virus CA-SP protein
試料
試料: T=1 icosahedral assembly of Rous sarcoma virus capsid proteins with spacer peptide
ジャーナル: J Virol / 年: 2013 タイトル: A two-pronged structural analysis of retroviral maturation indicates that core formation proceeds by a disassembly-reassembly pathway rather than a displacive transition. 著者: Paul W Keller / Rick K Huang / Matthew R England / Kayoko Waki / Naiqian Cheng / J Bernard Heymann / Rebecca C Craven / Eric O Freed / Alasdair C Steven / 要旨: Retrovirus maturation involves sequential cleavages of the Gag polyprotein, initially arrayed in a spherical shell, leading to formation of capsids with polyhedral or conical morphology. Evidence ...Retrovirus maturation involves sequential cleavages of the Gag polyprotein, initially arrayed in a spherical shell, leading to formation of capsids with polyhedral or conical morphology. Evidence suggests that capsids assemble de novo inside maturing virions from dissociated capsid (CA) protein, but the possibility persists of a displacive pathway in which the CA shell remains assembled but is remodeled. Inhibition of the final cleavage between CA and spacer peptide SP1/SP blocks the production of mature capsids. We investigated whether retention of SP might render CA assembly incompetent by testing the ability of Rous sarcoma virus (RSV) CA-SP to assemble in vitro into icosahedral capsids. Capsids were indeed assembled and were indistinguishable from those formed by CA alone, indicating that SP was disordered. We also used cryo-electron tomography to characterize HIV-1 particles produced in the presence of maturation inhibitor PF-46396 or with the cleavage-blocking CA5 mutation. Inhibitor-treated virions have a shell that resembles the CA layer of the immature Gag shell but is less complete. Some CA protein is generated but usually not enough for a mature core to assemble. We propose that inhibitors like PF-46396 bind to the Gag lattice where they deny the protease access to the CA-SP1 cleavage site and prevent the release of CA. CA5 particles, which exhibit no cleavage at the CA-SP1 site, have spheroidal shells with relatively thin walls. It appears that this lattice progresses displacively toward a mature-like state but produces neither conical cores nor infectious virions. These observations support the disassembly-reassembly pathway for core formation.
名称: T=1 icosahedral assembly of Rous sarcoma virus capsid proteins with spacer peptide タイプ: sample / ID: 1000 集合状態: T=1 icosahedral shell with 60 subunits forming 12 pentamers Number unique components: 1
分子量
理論値: 1.51 MDa
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超分子 #1: Rous sarcoma virus
超分子
名称: Rous sarcoma virus / タイプ: virus / ID: 1 / 詳細: icosahedral assembly of CA-SP protein / NCBI-ID: 11886 / 生物種: Rous sarcoma virus / ウイルスタイプ: VIRUS-LIKE PARTICLE / ウイルス・単離状態: SPECIES / ウイルス・エンベロープ: No / ウイルス・中空状態: Yes
宿主
生物種: Gallus gallus (ニワトリ) / 別称: VERTEBRATES
Host system
生物種: Escherichia coli (大腸菌) / 組換株: BL21
分子量
理論値: 1.51 MDa
ウイルス殻
Shell ID: 1 / T番号(三角分割数): 1
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実験情報
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構造解析
手法
クライオ電子顕微鏡法
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
2 mg/mL
緩衝液
pH: 7.5 詳細: 10 mM Tris-HCl, 75 mM sodium chloride, 0.05 mM EDTA, 0.5 M sodium phosphate
グリッド
詳細: Holey carbon film on R2/2 400 mesh copper grid
凍結
凍結剤: ETHANE / チャンバー内湿度: 90 % / チャンバー内温度: 93.15 K / 装置: LEICA KF80 / 詳細: Vitrification carried out in nitrogen atmosphere. 手法: 4.0 microliter sample dropped onto grid, blotted on one side for 2 second, then plunged.
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電子顕微鏡法
顕微鏡
FEI/PHILIPS CM200FEG
温度
平均: 93.15 K
日付
2011年9月24日
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: NIKON SUPER COOLSCAN 9000 デジタル化 - サンプリング間隔: 6.35 µm / 実像数: 17 / 平均電子線量: 15 e/Å2 / ビット/ピクセル: 16