ジャーナル: Sci Rep / 年: 2018 タイトル: An Algorithm for Enhancing the Image Contrast of Electron Tomography. 著者: Hao Wu / Xiaobo Zhai / Dongsheng Lei / Jianfang Liu / Yadong Yu / Rongfang Bie / Gang Ren / 要旨: Three-dimensional (3D) reconstruction of a single protein molecule is essential for understanding the relationship between the structural dynamics and functions of the protein. Electron tomography ...Three-dimensional (3D) reconstruction of a single protein molecule is essential for understanding the relationship between the structural dynamics and functions of the protein. Electron tomography (ET) provides a tool for imaging an individual particle of protein from a series of tilted angles. Individual-particle electron tomography (IPET) provides an approach for reconstructing a 3D density map from a single targeted protein particle (without averaging from different particles of this type of protein), in which the target particle was imaged from a series of tilting angles. However, owing to radiation damage limitations, low-dose images (high noise, and low image contrast) are often challenging to be aligned for 3D reconstruction at intermediate resolution (1-3 nm). Here, we propose a computational method to enhance the image contrast, without increasing any experimental dose, for IPET 3D reconstruction. Using an edge-preserving smoothing-based multi-scale image decomposition algorithm, this method can detect the object against a high-noise background and enhance the object image contrast without increasing the noise level or significantly decreasing the image resolution. The method was validated by using both negative staining (NS) ET and cryo-ET images. The successful 3D reconstruction of a small molecule (<100 kDa) indicated that this method can be used as a supporting tool to current ET 3D reconstruction methods for studying protein dynamics via structure determination from each individual particle of the same type of protein.
DNA origami Bennett linkage was diluted to ~2 nM with Tris-Borate-EDTA (TBE) buffer containing 11 mM MgCl2
切片作成
その他: NO SECTIONING
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電子顕微鏡法
顕微鏡
FEI TECNAI F20
撮影
フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) 平均電子線量: 0.69 e/Å2
電子線
加速電圧: 200 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD / 倍率(公称値): 19000
実験機器
モデル: Tecnai F20 / 画像提供: FEI Company
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画像解析
詳細
X-ray speckles in images were removed before CTF correction.
最終 再構成
アルゴリズム: FOURIER SPACE / 解像度のタイプ: BY AUTHOR / 解像度: 97.4 Å / 解像度の算出法: FSC 0.5 CUT-OFF 詳細: The 3D reconstruction was performed by using Individual-Particle Electron Tomography (IPET). The obtained 3D map was low-pass filtered to 8 nm 使用した粒子像数: 57