Design of a Molecular Support for Cryo-EM Structure Determination
Design of a molecular support for cryo-EM structure determination Thomas G. Martina, Tanmay A. M. Bharata,b, Andreas C. Joergera,c, Xiao-chen Baia, Florian Praetoriusd, Alan R. Fershta, Hendrik Dietzd,1, and Sjors H. W. Scheresa,1 aMedical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom; bSir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom; cGerman Cancer Consortium (DKTK), Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, 60438 Frankfurt am Main, Germany; and dPhysik Department, Walter Schottky Institute, Technische Universität München, 85748 Garching near Munich, Germany Edited by Fred J. Sigworth, Yale University, New Haven, CT, and approved October 13, 2016 (received for review August 2, 2016) Despite the recent rapid progress in cryo-electron microscopy angles are, therefore, determined a posteriori by image-pro- (cryo-EM), there still exist ample opportunities for improvement cessing algorithms that match the experimental projection of in sample preparation. Macromolecular complexes may disassociate every individual particle with projections of a 3D model (7). or adopt nonrandom orientations against the extended air–water However, the projection-matching procedure is ultimately ham- interface that exists for a short time before the sample is frozen. We pered by radiation damage. Because the electrons that are used designed a hollow support structure using 3D DNA origami to pro- for imaging destroy the very structures of interest (see ref. 8 for a tect complexes from the detrimental effects of cryo-EM sample recent review), one needs to limit carefully the number of elec- preparation. For a first proof-of-principle, we concentrated on the trons used for imaging.
[Show full text]