Ashley Baxter of the Wittenberg Research Group

Graduate student Ashley Baxter will present

"A Sampling of the Use of Cryo-EM to Provide Structural Insights into Biomolecular Systems"

on April 3, 2018 at 4:10 PM in Neville Hall, Room 3.



Cyro-electron microscopy (cryo-EM) is a technique that structural biologists have been exploiting for decades to gain further insights into biochemical marcomolecules.  Cyro-EM is a subset of electron microscopy, in that a beam of electrons is aimed at a sample and the nonscattered electrons are absorbed onto an electromagnetic plate, providing a shadow of an image of the sample.  Techniques that have been employed in the past, such as X-ray crystallography and NMR, have limitations or shortcomings that cryo-EM can overcome.  Cyro-EM allows scientists to visualize molecules in their native state and near-atomic resolution, which helps elucidate certain structural features.  By broadening the structural understanding of biomacromolecules, their function can also be further understood.  In this seminar, I will be highlighting three different protein macromolecules and how cryo-EM was used to give structural and thus functional insights into them.  Firstly, I will talk about the structural differences of actin after it has been oxidized by a redox enzyme called Mical, and how these differences cause the instability of the protein. Secondly, I will discuss the structure of the catalytic subunit of oligosaccharyltransferase, which is the protein complex that catalyzes Nlinked glycosylation.  Lastly, I will discuss the structure of the AMPAR ion channel, which plays a role in excitatory neurotransmission, and the global conformational shifts that occur upon ligand binding.


  1. Grintsevich, Elena E.; Ge, Peng; Sawaya, Michael R.; Yesiyurt, Hunkar Gizem; Terman, Jonathan R.; Zhou, Z. Hong; Reisler, Emil. Nature. 2017, 8: 2183, 1-10.
  2. Wild, Rebekka; Kowal, Julia; Eyring, Jillianne; Ngwa, Elsy, M.; Aebi, Markus; Locher, Kaspar P. Science. 2018, 359: 6375, 545-550.
  3. Twomey, Edward C.; Yelshanskaya, Maria V.; Grassucci, Robert A.; Frank, Joachim; Sobolevsky, Alexander I. Nature. 2017, 549, 60-65. 


Tuesday, April 3, 2018


Ashley Baxter