Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 12: Single Molecule Biophysics

BP 12.1: Hauptvortrag

Montag, 7. März 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 Alsteens^1,2, 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.