ジャーナル: Science / 年: 2008 タイトル: The flavivirus precursor membrane-envelope protein complex: structure and maturation. 著者: Long Li / Shee-Mei Lok / I-Mei Yu / Ying Zhang / Richard J Kuhn / Jue Chen / Michael G Rossmann / 要旨: Many viruses go through a maturation step in the final stages of assembly before being transmitted to another host. The maturation process of flaviviruses is directed by the proteolytic cleavage of ...Many viruses go through a maturation step in the final stages of assembly before being transmitted to another host. The maturation process of flaviviruses is directed by the proteolytic cleavage of the precursor membrane protein (prM), turning inert virus into infectious particles. We have determined the 2.2 angstrom resolution crystal structure of a recombinant protein in which the dengue virus prM is linked to the envelope glycoprotein E. The structure represents the prM-E heterodimer and fits well into the cryo-electron microscopy density of immature virus at neutral pH. The pr peptide beta-barrel structure covers the fusion loop in E, preventing fusion with host cell membranes. The structure provides a basis for identifying the stages of its pH-directed conformational metamorphosis during maturation, ending with release of pr when budding from the host.
THE AUTHOR STATES THAT THE DIFFERENCES BETWEEN THE SEQUENCE AND THE SEQUENCE IN THE DATABASE ...THE AUTHOR STATES THAT THE DIFFERENCES BETWEEN THE SEQUENCE AND THE SEQUENCE IN THE DATABASE REFERENCE ARE DUE TO THE DIFFERENCES BETWEEN VIRUS STRAINS.
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実験情報
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実験
実験
手法: 電子顕微鏡法
EM実験
試料の集合状態: PARTICLE / 3次元再構成法: 単粒子再構成法
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試料調製
構成要素
名称: DENGUE-2 IMMATURE PARTICLE / タイプ: VIRUS 詳細: THE SAMPLES WERE PRODUCED BY ADDING AMMONIUM CHLORIDE TO THE MEDIA IN THE LATE INFECTION STAGE
ウイルスについての詳細
ホストのカテゴリ: VERTEBRATES / 単離: STRAIN / タイプ: VIRION
天然宿主
生物種: Aedes aegypti / 株: C6/36
緩衝液
pH: 7.6 / 詳細: 12 mM Tris-HCl, 120 mM NaCl, 1 mM EDTA
モード: BRIGHT FIELD / 倍率(公称値): 45000 X / 倍率(補正後): 33000 X / 最大 デフォーカス(公称値): 3640 nm / 最小 デフォーカス(公称値): 1662 nm / Cs: 2 mm
試料ホルダ
温度: 100 K / 傾斜角・最大: 0 ° / 傾斜角・最小: 0 °
撮影
電子線照射量: 15 e/Å2 / フィルム・検出器のモデル: KODAK SO-163 FILM
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解析
EMソフトウェア
ID
名称
カテゴリ
1
EMfit
モデルフィッティング
2
SPIDER
3次元再構成
3
Xmipp
3次元再構成
対称性
点対称性: I (正20面体型対称)
3次元再構成
解像度: 12.5 Å / 粒子像の数: 2741 / 対称性のタイプ: POINT
原子モデル構築
プロトコル: RIGID BODY FIT / 空間: REAL Target criteria: USE PROGRAM EMFIT, SEARCH FOR POSTION WHERE ATOMS OCCUPY MOST EM DENSITY PEAKS 詳細: METHOD--SEE PRIMARY CITATION REFINEMENT PROTOCOL--RIGID BODY