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BP: Fachverband Biologische Physik
BP 12: Single Molecule Biophysics
BP 12.1: Invited Talk
Monday, March 7, 2016, 15:00–15:30, H45
Imaging of G-protein coupled receptors while quantifying their ligand-binding free energy landscape to mutiple ligands — •Daniel J. Müller1, David Alsteens1,2, Moritz Pfreundschuh1, Patrizia M. Spoerri1, Shaun R. Coughlin3, Cheng Zhang4, and Brian K. Kobilka4 — 1ETH Zurich, Switzerland — 2University Leuven, Belgium — 3University of California San Francisco, USA — 4Stanford University School of Medicine, USA
Imaging native membrane receptors and testing how they interact with ligands is of fundamental interest in life sciences, but has proven remarkably difficult to accomplish. Here, we introduce experimental and theoretical developments that allow atomic force microscopy (AFM) to simultaneously image native human protease-activated receptors (PAR1) in the functionally important lipid membrane and to quantify their dynamic binding strength to native and synthetic ligands. These binding strengths provide kinetic and thermodynamic parameters of individual ligand-receptor complexes. Recorded in the absence and presence of antagonists, the values describe the ligand-binding free energy landscape of native and synthetic ligands to the G-protein-coupled receptor with remarkable accuracy. We further address the challenge and introduce multifunctional high-resolution AFM to image PAR1 and to simultaneously localize and quantify their binding to two different ligands. Our nanoscopic method opens an exciting avenue to directly image and characterize ligand-binding of native membrane receptors.