Effects of cryo-EM cooling on structural ensembles.
Effects of cryo-EM cooling on structural ensembles.
复制标题
DOI：
10.1038/s41467-022-29332-2
复制
发表时间：
2022-03-31
影响因子：
16.6
通讯作者：
Grubmüller H
中科院分区：
文献类型：
--
作者：
Bock LV;Grubmüller H
低温电子显微镜（cryo-EM）的结构测定提供了原子分辨率的结构异质性和系综信息。为了获得大分子的低温EM图像，样品首先被快速冷却到低温温度。在冷却过程中，结构总体受到多大程度的扰动目前尚不清楚。在这里，为了量化冷却的影响，我们结合了连续模型计算的温度下降，分子动力学模拟的核糖体复合物之前和冷却过程中的动力学模型。我们的研究结果表明，三种效应显着有助于缩小的结构合奏：热收缩，减少局部势威尔斯内的热运动，并通过克服分离的自由能障碍的平衡成较低的自由能构象。在冷却过程中，低于10 kJ/mol的势垒高度被发现被克服，这是预期的，以减少B-因子在合奏成像的冷冻EM。我们的方法现在能够量化的异质性的室温合奏从冷冻EM结构。快速的温度下降，在暴跌冻结影响的结构合奏获得的冷冻EM。为了量化扰动的程度，Bock和Grubmüller结合了连续计算、MD模拟和动力学模型。
Structure determination by cryo electron microscopy (cryo-EM) provides information on structural heterogeneity and ensembles at atomic resolution. To obtain cryo-EM images of macromolecules, the samples are first rapidly cooled down to cryogenic temperatures. To what extent the structural ensemble is perturbed during cooling is currently unknown. Here, to quantify the effects of cooling, we combined continuum model calculations of the temperature drop, molecular dynamics simulations of a ribosome complex before and during cooling with kinetic models. Our results suggest that three effects markedly contribute to the narrowing of the structural ensembles: thermal contraction, reduced thermal motion within local potential wells, and the equilibration into lower free-energy conformations by overcoming separating free-energy barriers. During cooling, barrier heights below 10 kJ/mol were found to be overcome, which is expected to reduce B-factors in ensembles imaged by cryo-EM. Our approach now enables the quantification of the heterogeneity of room-temperature ensembles from cryo-EM structures. The rapid temperature drop during plunge-freezing affects the structural ensembles obtained by cryo-EM. To quantify the extent of perturbation, Bock and Grubmüller combined continuum calculations, MD simulations, and kinetic models.
登录
查看更多内容
影响因子：
3
作者：
Frolov, EN;Gvosdev, R;Parak, FG
通讯作者：
Parak, FG
影响因子：
16.6
作者：
Carbone CE;Loveland AB;Gamper HB Jr;Hou YM;Demo G;Korostelev AA
通讯作者：
Korostelev AA
影响因子：
5.6
作者：
Fraser JS;Lindorff-Larsen K;Bonomi M
通讯作者：
Bonomi M
影响因子：
6.8
作者：
Bonomi, Massimiliano;Vendruscolo, Michele
通讯作者：
Vendruscolo, Michele
影响因子：
2.2
作者：
BERRIMAN, J;UNWIN, N
通讯作者：
UNWIN, N