Biophysical Society Thematic Meeting | Trieste 2024

Emerging Theoretical Approaches to Complement Single-Particle Cryo-EM

Friday Speaker Abstracts

ADVANCING STRUCTURAL INSIGHTS INTO SMALL MEMBRANE TRANSPORTERS THROUGH SP-CRYOEM: UNRAVELING THE REGULATORY MECHANISMS OF SLC26 FAMILY Jakub Rzeszótko 1 ; Dovile Januliene 2 ; Yung-Ning Chang 3 ; Katharina Holzhüter 4 ; Benedikt T Kuhn 1 ; Arne Möller 2 ; Eric R Geertsma 1 ; 1 Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany 2 University of Osnabrück, Department of Structural Biology, Osnabrück, Germany 3 Nuvisan Pharma Services, Berlin, Germany 4 Goethe University, Institute of Biophysical Chemistry, Frankfurt, Germany The structural characterization of small membrane proteins via SP-CryoEM presents unique challenges. Additionally, the dynamic conformational landscape of membrane transporters adds to the complexity. Our research group tackles these obstacles through an approach combining extensive sample preparation and biochemical characterization, and the application of conformation-specific nanobody binders. This methodology, coupled with SP-cryoEM and advanced in vitro transport assays, enables us to study the structure-function relationships within the Solute Carrier Family 26 (SLC26). The SLC26 family is crucial for maintaining ion homeostasis and pH regulation, critical for numerous physiological processes, particularly during development. These secondary transporters facilitate the translocation of various anions across cellular membranes. Its C-terminal cytoplasmic STAS domain plays important role for their functionality, including trafficking, activity regulation, and protein interactions. My research is dedicated to investigating the regulatory mechanisms of the STAS domain and its evolutionary trajectory. This investigation is crucial for understanding the broader functional dynamics of the SLC26 family and holds potential for therapeutic advancements targeting SLC26-related disorders such as chondrodysplasia and deafness. Furthermore, this project underscores the significance of exploring prokaryotic SLC26 homologs. Our discovery of a novel dimer interface in the cyanobacterial bicarbonate transporter BicA provides fresh insights into the regulatory role of the STAS domain. By leveraging cutting-edge SP-CryoEM and innovative biochemical strategies, our work advances the frontier of membrane protein research. It offers promising avenues for therapeutic intervention and deepens our understanding of protein structure-function relationship.

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