Imaging RNA Structures and Folding Intermediates using Electron Cryo-Microscopy
Tuesday, October 30, 2007 - 3:50pm - 4:20pm
We investigate the applicability of electron cryomicroscopy (cryo-EM) with single particle reconstruction in the RNA structural studies as small as 154 residues (~50 kD). This size is at least two-fold smaller than the generally conceived limits for single-particle image reconstruction by cryo-EM of macromolecules. For the Specificity and Catalytic domain of bacterial RNase P RNA, single-particle reconstruction of the native structures exhibits good agreement with their respective crystal structures. For the major thermodynamic folding intermediate of the /B. subtilis/ specificity domain, the single-particle reconstruction has considerable similarity to the previously proposed structural models of this intermediate. These results indicate that cryo-EM can directly image conformations of relatively small RNA molecules in different structural and functional states.