Structural Mechanism of an Efficacy Photoswitch Targeting the β <sub>2</sub> ‐adrenergic Receptor
Abstract
ABSTRACT The field of photopharmacology develops light‐responsive drugs that can modulate protein activity, enabling precise and dynamic investigations of their roles in health and disease. Adrenergic receptors are prominent targets for this approach because they are prototypical G protein‐coupled receptors with high clinical relevance in bronchial and cardiovascular diseases. Here, we employed the azobenzene‐based compound photoazolol‐1 in combination with time‐resolved serial crystallography at X‐ray free‐electron lasers to resolve the molecular mechanisms by which photoswitchable β‐blockers modulate activity of the β 2 ‐adrenoceptor (β 2 AR). Time‐resolved structures of the receptor bound to trans ‐photoazolol‐1 (pre‐photoconversion), a strained intermediate in the nanosecond range, and the fully photoisomerized cis ‐photoazolol‐1 reveal how isomerization of the azobenzene moiety induces distinct conformational changes within the orthosteric ligand binding pocket. Within seconds, light‐excited photoazolol‐1 adopts a new binding pose, altering interactions with extracellular loop 2 and shifting the positions of transmembrane helices 5, 6, and 7. Functional assays of β 2 AR in cellular membranes show that photoazolol‐1 acts as an efficacy photoswitch, changing from an inverse agonist to a neutral antagonist upon isomerization without leaving the binding pocket. In combination, these findings suggest a molecular mechanism for activity modulation via efficacy photoswitches and provide a framework for designing ligands that exploit light‐driven transitions within the binding pocket to achieve spatiotemporal control of receptor function.
Article Details
Authors (30)
Robin Stipp
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Quentin Bertrand
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Matilde Trabuco
LeadXpro AG Villigen Switzerland
Anna Duran‐Corbera
MCS, Laboratory of Medicinal Chemistry Institute For Advanced Chemistry of Catalonia (IQAC), CSIC Barcelona Spain
Maria Tindara Ignazzitto
MCS, Laboratory of Medicinal Chemistry Institute For Advanced Chemistry of Catalonia (IQAC), CSIC Barcelona Spain
Hannah Glover
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Fabienne Stierli
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Juanlo Catena
MCS, Laboratory of Medicinal Chemistry Institute For Advanced Chemistry of Catalonia (IQAC), CSIC Barcelona Spain
Melissa Carrillo
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Sina Hartmann
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Hans‐Peter Seidel
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Matthias Mulder
Thomas Mason
Yasushi Kondo
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Maximillian Wranik
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Martin Appleby
Christoph Sager
LeadXpro AG Villigen Switzerland
Raymond Sierra
Linac Coherent Light Source SLAC National Accelerator Laboratory Menlo Park California USA
Gregory Gate
Linac Coherent Light Source, SLAC National Accelerator Laboratory 5 , 2575 Sand Hill Road, Menlo Park, California 94025,
Pamela Schleissner
Linac Coherent Light Source SLAC National Accelerator Laboratory Menlo Park California USA
Xinxin Cheng
Tobias Weinert
Robert Cheng
Sandra Mous
John H. Beale
Michal Kepa
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland
Amadeu Llebaria
Medicinal Chemistry and Synthesis (MCS) Laboratory, Institute for Advanced Chemistry of Catalonia (IQAC−CSIC), Carrer de Jordi Girona, 20, 08034 Barcelona, Spain
Michael Hennig
LeadXpro AG, Park Innovaare
Xavier Rovira
Medicinal Chemistry and Synthesis (MCS) Laboratory, Institute for Advanced Chemistry of Catalonia (IQAC−CSIC), Carrer de Jordi Girona, 20, 08034 Barcelona, Spain
Joerg Standfuss
PSI Center for Life Sciences, Paul Scherrer Institute Villigen Switzerland