当前位置:科学网首页 > 小柯机器人 >详情
Q值-标定cryo-EM图谱原子可分辨性新方法
作者:小柯机器人 发布时间:2020/2/13 9:58:51

美国斯坦福大学Wah ChiuGrigore Pintilie研究组利用Q值标定冷冻电镜(cryo-EM)图谱中的原子可分辨性。相关论文2020210日发表于国际学术期刊《自然方法学》。

他们引入了一个定量参数来表征冷冻电镜图(cryo-EM)(图Q值)中单个原子的可分辨性。可以使用适合或源自cryo-EM图的模型来计算蛋白质、核酸、水、配体和其他溶剂原子中原子的Q值。Q值也可以取平均值以表示更大的特征,例如整个残基和核苷酸。在整个模型中取平均值,Q值与蛋白质和RNA的cryo-EM图的估计分辨率非常相关。假设从中计算出的模型与该图非常吻合,则Q值可用于衡量cryo-EM图中从整个大分子到单个原子的各种比例的可分辨性。对来自不同实验室的同一蛋白质的多个cryo-EM图进行的Q值分析证实了从侧链直至水和离子原子的结构特征的可再生性。

据介绍,冷冻电镜(cryo-EM)图现在可以实现单个原子的可分辨性。但是,可分辨性不一定在整个图谱上都是一致的。

附:英文原文

Title: Measurement of atom resolvability in cryo-EM maps with Q -scores

Author: Grigore Pintilie, Kaiming Zhang, Zhaoming Su, Shanshan Li, Michael F. Schmid, Wah Chiu

Issue&Volume: 2020-02-10

Abstract: Cryogenic electron microscopy (cryo-EM) maps are now at the point where resolvability of individual atoms can be achieved. However, resolvability is not necessarily uniform throughout the map. We introduce a quantitative parameter to characterize the resolvability of individual atoms in cryo-EM maps, the map Q-score. Q-scores can be calculated for atoms in proteins, nucleic acids, water, ligands and other solvent atoms, using models fitted to or derived from cryo-EM maps. Q-scores can also be averaged to represent larger features such as entire residues and nucleotides. Averaged over entire models, Q-scores correlate very well with the estimated resolution of cryo-EM maps for both protein and RNA. Assuming the models they are calculated from are well fitted to the map, Q-scores can be used as a measure of resolvability in cryo-EM maps at various scales, from entire macromolecules down to individual atoms. Q-score analysis of multiple cryo-EM maps of the same proteins derived from different laboratories confirms the reproducibility of structural features from side chains down to water and ion atoms.

DOI: 10.1038/s41592-020-0731-1

Source: https://www.nature.com/articles/s41592-020-0731-1

期刊信息

Nature Methods:《自然—方法学》,创刊于2004年。隶属于施普林格·自然出版集团,最新IF:28.467
官方网址:https://www.nature.com/nmeth/
投稿链接:https://mts-nmeth.nature.com/cgi-bin/main.plex