This year's annual Reed M. Izatt and James J. Christensen Lecture Series will feature Grant Jensen, Dean of the College of Physical and Mathematical Sciences.
Abstract: Recently electron cryotomography (cryo-ET) has made it possible to visualize large macromolecular machines inside intact cells in a near-native, "frozen-hydrated" state in 3-D to a few nanometers resolution. Increasingly, atomic models of individual proteins and smaller complexes obtained by X-ray crystallography, NMR spectroscopy, AlphaFold, or other methods can be fit into cryotomograms to reveal how the various pieces work together inside cells. To illustrate these points, I will present an example from our recent work on the bacterial Type IV secretion system (T4SS). The Legionella pneumophila Dot/Icm T4SS delivers effector proteins into host cells during infection. Despite its significance as a potential drug target, our current understanding of its structure is limited to isolated fragments. I will report how my group used subtomogram averaging and integrative modeling to construct a nearly complete model of the Dot/Icm T4SS accounting for 17 protein components. Technologically, the work illustrates how the structures of very large, heterogeneous, and flexible cellular nanomachines can now be characterized in vivo.
The Izatt-Christensen Lectures are named after two internattionally recognized members of the university, Reed Izatt of the Department of Chemistry and Biochemistry and James Christensen of the Department of Chemical Engineering. The two professors started a joint research program in chemical thermodynamics and chemical separations which received international recognition. The long-time colleagues also guided more than 60 graduate students through their M.S. and Ph.D. degrees in chemistry and chemical engineering during their time at BYU. Christensen passed away unexpectedly in September 1987.
Zoom Information
Link: https://byu.zoom.us/j/93020191162
Meeting code: 930 2019 1162