National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
R01HL115153
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM104427
米国
National Institutes of Health/National Institute of Mental Health (NIH/NIMH)
R01MH077303
米国
National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Disease (NIH/NIDDK)
R01DK042667
米国
引用
ジャーナル: Nat Commun / 年: 2024 タイトル: Non-averaged single-molecule tertiary structures reveal RNA self-folding through individual-particle cryo-electron tomography. 著者: Jianfang Liu / Ewan K S McRae / Meng Zhang / Cody Geary / Ebbe Sloth Andersen / Gang Ren / 要旨: Large-scale and continuous conformational changes in the RNA self-folding process present significant challenges for structural studies, often requiring trade-offs between resolution and ...Large-scale and continuous conformational changes in the RNA self-folding process present significant challenges for structural studies, often requiring trade-offs between resolution and observational scope. Here, we utilize individual-particle cryo-electron tomography (IPET) to examine the post-transcriptional self-folding process of designed RNA origami 6-helix bundle with a clasp helix (6HBC). By avoiding selection, classification, averaging, or chemical fixation and optimizing cryo-ET data acquisition parameters, we reconstruct 120 three-dimensional (3D) density maps from 120 individual particles at an electron dose of no more than 168 eÅ, achieving averaged resolutions ranging from 23 to 35 Å, as estimated by Fourier shell correlation (FSC) at 0.5. Each map allows us to identify distinct RNA helices and determine a unique tertiary structure. Statistical analysis of these 120 structures confirms two reported conformations and reveals a range of kinetically trapped, intermediate, and highly compacted states, demonstrating a maturation folding landscape likely driven by helix-helix compaction interactions.
超分子 #1: RNA Origami 6 Helix Bundle with Clasp (6HBC)
超分子
名称: RNA Origami 6 Helix Bundle with Clasp (6HBC) / タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all 詳細: The RNA was transcribed from linearized DNA template using T7 RNA polymerase purified in house.
凍結剤: ETHANE / チャンバー内湿度: 90 % / チャンバー内温度: 277 K / 装置: LEICA EM GP
詳細
In vitro transcribed RNA was purified by size exclusion chromatography and spin concentrated in amicon spin columns.
切片作成
その他: NO SECTIONING
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
撮影
フィルム・検出器のモデル: GATAN K3 BIOQUANTUM (6k x 4k) 撮影したグリッド数: 1 / 実像数: 21 / 平均露光時間: 0.88 sec. / 平均電子線量: 8.0 e/Å2
電子線
加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN
電子光学系
C2レンズ絞り径: 50.0 µm / 照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD / Cs: 2.7 mm / 倍率(公称値): 81000
試料ステージ
試料ホルダーモデル: FEI TITAN KRIOS AUTOGRID HOLDER
実験機器
モデル: Titan Krios / 画像提供: FEI Company
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画像解析
詳細
Motion correction of the multi-frame movie was conducted by MotionCor2. The tilt series of whole micrographs were initial aligned by IMOD. Additionally, to reduce the image noise, tilt series were further conducted by a machine learning, a median-filter process and a contrast enhancement method.
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: 25.0 Å / 解像度の算出法: FSC 0.5 CUT-OFF 詳細: The targeted images of individual particle were reconstructed by Individual-Particle Electron Tomography (IPET). To reduce the missing-wedge artifact caused by the limited tilt angle range, ...詳細: The targeted images of individual particle were reconstructed by Individual-Particle Electron Tomography (IPET). To reduce the missing-wedge artifact caused by the limited tilt angle range, the final 3D map was submitted to a low-tilt tomographic 3D reconstruction method (LoTToR). IPET 3D map was low-pass filtered to 0.8 nm following by Gaussian filtering (standard deviation is 3.0) and median filter (3x3x3) using EMAN and UCSF Chimera, and displayed by Chimera with applied the hidden dust function. 使用した粒子像数: 21