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BP: Fachverband Biologische Physik

BP 14: Posters: Protein Structure and dynamics

BP 14.15: Poster

Tuesday, April 1, 2014, 09:30–12:30, P1

Sorting cryo-EM images into classes of similar molecular conformations — •Michaela Spiegel¹ and Gunnar Schröder^{1, 2} — ¹ICS-6 Computational Structural Biology, Forschungszentrum Jülich, Germany — ²Physics Department, Heinrich-Heine-Universität Düsseldorf, Germany

The resolutions of density maps which are reconstructed from single-particle cryoelectron microscopy (cryo-EM) images are often limited by the conformational heterogeneity of the biological macromolecules. To increase the resolution, the images have to be sorted into groups of similar conformations. The common approaches of sorting images typically compare densities (either in 2D or 3D). However, a large difference in conformation does not necessarily lead to a large difference in density. We are developing a new sorting method that is based on comparing conformations. For this we are using a bootstrapping approach and refine pseudo-atomic models against an ensemble of bootstrapped density maps. These models capture the conformational variance and can be used for sorting the images. This procedure also reveals the conformational heterogeneity and is able to determine global conformational motions of large macromolecular structures and assemblies.