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Workshops

Interactions and Transport of Charged Species in Bulk and at Interfaces

July 4, 2016 to July 7, 2016
Location : CECAM-AT

PROTEIN STRUCTURE AND DYNAMICS FROM SINGLE-PARTICLE CRYO-EM DATA

Gunnar Schroeder
Forschungszentrum Juelich, Germany

Abstract

One of the biggest challenges in the analysis of cryo-EM images is the heterogeneity and flexibility of the molecules, which on the one hand severely limits the achievable resolution but on the other hand reports on conformational dynamics. A computational approach will be presented to reduce the conformational variance of a set of single-particle images with the goal of increasing the resolution. First the conformational variance of a molecule is reconstructed from the variance of the density. The information on conformational variance is then used to extensively classify the images into a number of different classes. In a next step, the individual 3D density reconstructions from all classes are recombined into one single (higher resolution) reconstruction by a novel flexible averaging procedure. In the flexible averaging the density grids of two maps are elastically deformed to account for large scale conformational differences thereby reducing the conformational variance of a data set. The goal is to improve the resolution and at the same time to gain a complete picture of the conformational variance of a macromolecule.