[대학원 생명과학과 세미나 안내]
연사 : Egelman, H. Edward 교수 (Univ. of Virginia)
연제 : Cryo-EM of Helical Polymers at Near Atomic Resolution Yields Surprises:From Microbial Nanowires to Indestructible Pili
일시 : 2019년 6월 18일 (화) 오전 11시
장소 : 하나과학관 A동 307호
초청교수 : 우재성 교수
Abstract
Large amounts of protein in eukaryotic, bacterial and archaeal cells is often found in the form of helical polymers. Viruses infecting these cells can also be helical. We have been using cryo-EM to study the structure and function of many of these polymers. Since the introduction of direct electron detectors about six years ago, there has been a “resolution revolution” where near-atomic levels of resolution can now almost routinely be achieved for many macromolecular complexes. While some of these complexes can, in principle, be crystallized, cryo-EM has emerged as the method of choice for structural studies of such complexes as it does not require crystallization, uses far less sample, and is much faster. But for helical polymers most can never be crystallized and cryo-EM is not only the preferred method but the only method available for reaching near-atomic resolution. I will describe our most recent applications of cryo-EM to a range of systems, from viruses that infect organisms living in nearly boiling acid (1-3), to an archaeal pilus that is nearly indestructible (4), to “microbial nanowires” that conduct electrons (5). All of these studies provide not only new understanding of biology and evolution, but yield insights into novel structures that can have applications to drug delivery, biomedical engineering and nanotechnology.
1. Liu Y, Osinski T, Wang F, Krupovic M, Schouten S, Kasson P, Prangishvili D, & Egelman EH (2018) Structural conservation in a membrane-enveloped filamentous virus infecting a hyperthermophilic acidophile. Nature communications 9(1):3360.
2. Kasson P, DiMaio F, Yu X, Lucas-Staat S, Krupovic M, Schouten S, Prangishvili D, & Egelman EH (2017) Model for a novel membrane envelope in a filamentous hyperthermophilic virus. eLife 6:doi:10.7554/eLife.26268.
3. DiMaio F, Yu X, Rensen E, Krupovic M, Prangishvili D, & Egelman EH (2015) A Virus that Infects a Hyperthermophile Encapsidates A-Form DNA. Science 348:914-917.
4. Wang F, Cirvkaite-Krupovic, V., Kreutzberger, M., Su, Z., de Oliveira, G., Sherman, N., DiMaio, F., Wall, J., Prangishvili, D., Krupovic, M., Egelman, E.H. (2019) An extensively glycosylated archaeal pilus survives extreme conditions. Nature Microbiology in press.
5. Wang F, et al. (2019) Structure of Microbial Nanowires Reveals Stacked Hemes that Transport Electrons over Micrometers. Cell 177(2):361-369.e310.