ジャーナル: J Struct Biol / 年: 2019 タイトル: Using focus ion beam to prepare crystal lamella for electron diffraction. 著者: Heng Zhou / Zhipu Luo / Xueming Li / 要旨: Electron diffraction provides a powerful tool to solve the structures of small protein crystals. However, strong interactions between the electrons and the materials limit the application of the ...Electron diffraction provides a powerful tool to solve the structures of small protein crystals. However, strong interactions between the electrons and the materials limit the application of the electron crystallographic method on large protein crystals with micrometer or larger sizes. Here, we used the focused ion beam (FIB) equipped on the scanning electron microscope (SEM) to mill a large crystal to thin lamella. The influences of the milling on the crystal lamella were observed and investigated, including radiation damage on the crystal surface during the FIB imaging, deformation of the thin crystal lamella, and variation in the diffraction intensities under electron radiation. These observations provide important information to optimize the FIB milling, and hence is important to obtain high-quality crystal samples for routine structure determination of protein crystals using the electron cryo-microscope.
∠α: 90 ° / ∠β: 90 ° / ∠γ: 90 ° / A: 69.31 Å / B: 69.31 Å / C: 104.12 Å / 空間群名: P43212 / 空間群番号: 96
CTF補正
タイプ: NONE
3次元再構成
解像度: 1.5 Å / 解像度の算出法: DIFFRACTION PATTERN/LAYERLINES / 対称性のタイプ: 3D CRYSTAL
原子モデル構築
プロトコル: FLEXIBLE FIT / 空間: RECIPROCAL
精密化
解像度: 1.5→12.31 Å / Cor.coef. Fo:Fc: 0.956 / Cor.coef. Fo:Fc free: 0.938 / SU B: 2.195 / SU ML: 0.077 / 交差検証法: THROUGHOUT / σ(F): 0 / ESU R: 0.087 / ESU R Free: 0.09 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS U VALUES : REFINED INDIVIDUALLY
Rfactor
反射数
%反射
Selection details
Rfree
0.2251
1893
5 %
RANDOM
Rwork
0.1868
-
-
-
obs
0.1888
35768
91.07 %
-
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: BABINET MODEL WITH MASK