Cryo-electron microscopy (cryo-EM) is an important biophysical technique that produces three-dimensional (3D) density maps at different resolutions. Because more and more models are being produced from cryo-EM density maps, validation of the models is becoming important. We propose a method for measuring local agreement between a model and the density map using the central axis of the helix. This method was tested using 19 helices from cryo-EM density maps between 5.5 A and 7.2 A resolution and 94 helices from simulated density maps. This method distinguished most of the well-fitting helices, although challenges exist for shorter helices. Validation, protein structure, secondary structure, image, fitting, cryo-electron microscopy
['Jing He', 'Stephanie Zeil', 'Hussam Hallak', 'Kele McKaig', 'Julio A. Kovacs', 'Willy Wriggers']
Comparison of an atomic model and its cryo-EM image at the central axis of a helix