Cryo-EM of Helical Polymers

• Authors: Fengbin Wang, University of Virginia; Ordy Gnewou, Emory University; Armin Solemanifar, Emory University; Vincent Conticello, Emory University; Edward H. Egelman, University of Virginia
• Journal Title: Chemical Review
• Publisher: American Chemical Society | 2022-02-08
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1021/acs.chemrev.1c00753
• Subjects: Biology, Molecular
• Keywords: cryo-EM; synthetic soft matter non-covalent polymers; helical macromolecular assemblies

Abstract

While the application of cryo-EM to helical polymers in biology has a long history, due to the huge number of helical macromolecular assemblies in viruses, bacteria, archaea and eukaryotes, the use of cryo-EM to study synthetic soft matter non-covalent polymers has been much more limited. This has mainly been due to the lack of familiarity with cryo-EM in the materials science and chemistry communities, in contrast to the fact that cryo-EM was developed as a biological technique. Nevertheless, the relatively few structures of self-assembled peptide nanotubes and ribbons solved at near-atomic resolution by cryo-EM have demonstrated that cryo-EM should be the method of choice for structural analysis of synthetic helical filaments. In addition, cryo-EM has also demonstrated that the self-assembly of soft matter polymers has enormous potential for polymorphism, something that may be obscured by techniques such as scattering and spectroscopy. These cryo-EM structures have revealed how far we currently are from being able to predict the structure of these polymers due to their chaotic self-assembly behavior.