Monday, June 26, 2023
11:00 AM
372 CAMP
Professor Gabriel A. Frank
Ben-Gurion University of the Negev, Israel
will speak on:
Novel Strategy for Analyzing Cryo-EM Data of Pseudo-Symmetric Oligomers
Gabriel A. Frank, Daniel Stein, Bruno Jean Jartoux, Ran Zalk, René Uebe, Raz Zarivach
Abstract: Ferritins are a family of nanocage proteins composed of 24 structurally similar but functionally different subunit types (named H and L) that store iron by sedimentation inside their inner cavity. It is unclear how the two subunit types are distributed in ferritins and what forces drive their organization. Answering these questions requires the structural determination of pseudo-symmetric oligomers, which is technically and conceptually challenging. Such a challenge is exacerbated in proteins like ferritin, with highly interconnected geometries and a vast number of configurations, rendering the determination of specific quaternary configurations meaningless.
In the first part of this seminar, we present a novel strategy for interpreting cryo-EM data of pseudo-symmetric oligomers by combining cryo-EM, graph theory, and a dedicated electron density analysis method. Using a bacterioferritin as a model, we show that a preferential organization of subunits is dictated by a global interaction network of the oligomer’s geometry, which is crucial for protein function and iron recruitment. In the second part, we discuss how high-resolution cryo-EM data helped us understand biomineralization processes and the function of intrinsically disordered proteins, and how unstructured regions of iron biomineralization proteins become more ordered in response to their interaction with nascent mineral particles.
This seminar is co-sponsored by the Northern New York Local Section of the American Chemical Society
