当前位置:科学网首页 > 小柯机器人 >详情
科学家利用电子计数的MicroED数据揭示大分子结构
作者:小柯机器人 发布时间:2022/5/31 13:10:46

美国加州大学洛杉矶分校Tamir Gonen研究团队利用电子计数的MicroED数据揭示大分子结构。相关论文于2022年5月30日在线发表在《自然—方法学》杂志上。

利用在计数模式下由直接电子检测器收集的微晶电子衍射(MicroED)数据,研究人员确定了两种球状蛋白的结构。研究人员使用了扫描电子显微镜(SEM)识别微晶体,并用聚焦离子束(FIB)进行减薄,以产生理想厚度的结晶层。通过使用超低的曝光率收集连续旋转数据,研究人员实现了衍射中的电子计数。

对于第一个样品,溶菌酶延伸到0.87埃的分辨率,一个只有三个丙氨酸残基的理想螺旋片段提供了初始相。这些相用密度修正法进行了改进,使整个原子结构得以自动建立。类似的方法在第二个大分子样品——蛋白酶K上获得了成功,衍射的分辨率为1.5埃。这些结果表明,大分子可以通过MicroED测定到亚埃的分辨率,并且ab initio phasing可以成功应用于计数数据。

附:英文原文

Title: Ab initio phasing macromolecular structures using electron-counted MicroED data

Author: Martynowycz, Michael W., Clabbers, Max T. B., Hattne, Johan, Gonen, Tamir

Issue&Volume: 2022-05-30

Abstract: Structures of two globular proteins were determined ab initio using microcrystal electron diffraction (MicroED) data that were collected on a direct electron detector in counting mode. Microcrystals were identified using a scanning electron microscope (SEM) and thinned with a focused ion beam (FIB) to produce crystalline lamellae of ideal thickness. Continuous-rotation data were collected using an ultra-low exposure rate to enable electron counting in diffraction. For the first sample, triclinic lysozyme extending to a resolution of 0.87, an ideal helical fragment of only three alanine residues provided initial phases. These phases were improved using density modification, allowing the entire atomic structure to be built automatically. A similar approach was successful on a second macromolecular sample, proteinase K, which is much larger and diffracted to a resolution of 1.5. These results demonstrate that macromolecules can be determined to sub-ngstrm resolution by MicroED and that ab initio phasing can be successfully applied to counting data.

DOI: 10.1038/s41592-022-01485-4

Source: https://www.nature.com/articles/s41592-022-01485-4

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