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Publication Abstract from PubMed

Single-particle cryo-electron microscopy (cryo-EM) allows the high-resolution structural determination of biological assemblies in a near-native environment. However, all high-resolution (better than 3.5A) cryo-EM structures reported to date were obtained by using 300kV transmission electron microscopes (TEMs). We report here the structures of a cypovirus capsid of 750-A diameter at 3.3-A resolution and of RNA-dependent RNA polymerase (RdRp) complexes within the capsid at 3.9-A resolution using a 200-kV TEM. The newly resolved structure revealed conformational changes of two subdomains in the RdRp. These conformational changes, which were involved in RdRp's switch from non-transcribing to transcribing mode, suggest that the RdRp may facilitate the unwinding of genomic double-stranded RNA. The possibility of 3-A resolution structural determinations for biological assemblies of relatively small sizes using cryo-EM at 200kV was discussed.

Near-Atomic Resolution Structure Determination of a Cypovirus Capsid and Polymerase Complex Using Cryo-EM at 200kV.,Li X, Zhou N, Chen W, Zhu B, Wang X, Xu B, Wang J, Liu H, Cheng L J Mol Biol. 2017 Jan 6;429(1):79-87. doi: 10.1016/j.jmb.2016.11.025. Epub 2016, Dec 1. PMID:27914893^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.