Ab initio phasing macromolecular structures using electron-counted MicroED data.

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 Å, 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 macrom

SUBMITTER: Martynowycz MW 

PROVIDER: S-EPMC9184278 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature