Premium
Using a partial atomic model from medium‐resolution cryo‐EM to solve a large crystal structure
Author(s) -
Fàbrega-Ferrer Montserrat,
Cuervo Ana,
Fernández Francisco J.,
Machón Cristina,
Pérez-Luque Rosa,
Pous Joan,
Vega M. Cristina,
Carrascosa José L.,
Coll Miquel
Publication year - 2021
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.374
H-Index - 138
ISSN - 2059-7983
DOI - 10.1107/s2059798320015156
Subject(s) - cryo electron microscopy , molecular replacement , resolution (logic) , rotation (mathematics) , atomic model , phaser , crystallography , physics , computer science , algorithm , materials science , biological system , chemistry , crystal structure , optics , artificial intelligence , atomic physics , nuclear magnetic resonance , biology
Medium‐resolution cryo‐electron microscopy maps, in particular when they include a significant number of α‐helices, may allow the building of partial models that are useful for molecular‐replacement searches in large crystallographic structures when the structures of homologs are not available and experimental phasing has failed. Here, as an example, the solution of the structure of a bacteriophage portal using a partial 30% model built into a 7.8 Å resolution cryo‐EM map is shown. Inspection of the self‐rotation function allowed the correct oligomerization state to be determined, and density‐modification procedures using rotation matrices and a mask based on the cryo‐EM structure were critical for solving the structure. A workflow is described that may be applicable to similar cases and this strategy is compared with direct use of the cryo‐EM map for molecular replacement.