National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
R01AI083255
米国
引用
ジャーナル: Viruses / 年: 2017 タイトル: Cleavage and Structural Transitions during Maturation of Staphylococcus aureus Bacteriophage 80α and SaPI1 Capsids. 著者: James L Kizziah / Keith A Manning / Altaira D Dearborn / Erin A Wall / Laura Klenow / Rosanne L L Hill / Michael S Spilman / Scott M Stagg / Gail E Christie / Terje Dokland / 要旨: In the tailed bacteriophages, DNA is packaged into spherical procapsids, leading to expansion into angular, thin-walled mature capsids. In many cases, this maturation is accompanied by cleavage of ...In the tailed bacteriophages, DNA is packaged into spherical procapsids, leading to expansion into angular, thin-walled mature capsids. In many cases, this maturation is accompanied by cleavage of the major capsid protein (CP) and other capsid-associated proteins, including the scaffolding protein (SP) that serves as a chaperone for the assembly process. bacteriophage 80α is capable of high frequency mobilization of mobile genetic elements called pathogenicity islands (SaPIs), such as SaPI1. SaPI1 redirects the assembly pathway of 80α to form capsids that are smaller than those normally made by the phage alone. Both CP and SP of 80α are N-terminally processed by a host-encoded protease, Prp. We have analyzed phage mutants that express pre-cleaved or uncleavable versions of CP or SP, and show that the N-terminal sequence in SP is absolutely required for assembly, but does not need to be cleaved in order to produce viable capsids. Mutants with pre-cleaved or uncleavable CP display normal viability. We have used cryo-EM to solve the structures of mature capsids from an 80α mutant expressing uncleavable CP, and from wildtype SaPI1. Comparisons with structures of 80α and SaPI1 procapsids show that capsid maturation involves major conformational changes in CP, consistent with a release of the CP N-arm by SP. The hexamers reorganize during maturation to accommodate the different environments in the 80α and SaPI1 capsids.
モード: BRIGHT FIELD / 倍率(公称値): 62000 X / 最大 デフォーカス(公称値): 2500 nm / 最小 デフォーカス(公称値): 1000 nm
撮影
電子線照射量: 25 e/Å2 / フィルム・検出器のモデル: KODAK SO-163 FILM
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解析
ソフトウェア
名称: REFMAC / バージョン: 5.8.0088 / 分類: 精密化
EMソフトウェア
ID
名称
バージョン
カテゴリ
詳細
1
EMAN
1.9
粒子像選択
4
EMAN
1.9
CTF補正
7
UCSF Chimera
1.10.2
モデルフィッティング
9
REFMAC
5.8.0158
モデル精密化
10
Coot
0.8.8
モデル精密化
11
Coot
0.8.6.1
モデル精密化
WinCoot (WindowsversionofCoot)
12
Auto3DEM
4.01
初期オイラー角割当
13
Auto3DEM
4.01
最終オイラー角割当
14
Auto3DEM
4.01
分類
15
Auto3DEM
4.01
3次元再構成
CTF補正
タイプ: PHASE FLIPPING ONLY
粒子像の選択
選択した粒子像数: 6471
対称性
点対称性: I (正20面体型対称)
3次元再構成
解像度: 8.4 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 6471 / 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
精密化
解像度: 8.4→8.4 Å / Cor.coef. Fo:Fc: 0.898 / SU B: 421.503 / SU ML: 2.971 立体化学のターゲット値: MAXIMUM LIKELIHOOD WITH PHASES 詳細: HYDROGENS HAVE BEEN USED IF PRESENT IN THE INPUT
Rfactor
反射数
%反射
Rwork
0.32913
-
-
obs
0.32913
8480
100 %
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK