Controlling the Dissociation of Ligands from the Adenosine A2A Receptor through Modulation of Salt Bridge Strength.
The association and dissociation kinetics of ligands binding to proteins vary considerably, but the mechanisms behind this variability are poorly understood, limiting their utilization for drug discovery. This is particularly so for G protein-coupled receptors (GPCRs) where high resolution structural information is only beginning to emerge. Engineering the human A2A adenosine receptor has allowed structures to be solved in complex with the reference compound ZM241385 and four related ligands at high resolution. Differences between the structures are limited, with the most pronounced being the interaction of each ligand with a salt bridge on the extracellular side of the receptor. Mutagenesis experiments confirm the role of this salt bridge in controlling the dissociation kinetics of the ligands from the receptor, while molecular dynamics simulations demonstrate the ability of ligands to modulate salt bridge stability. These results shed light on a structural determinant of ligand dissociation kinetics and identify a means by which this property may be optimized.
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Elena
E
Segala
Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University P.O. Box 9502, 2300 RA Leiden, the Netherlands.
Dong
D
Guo
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Robert K Y
RK
Cheng
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Andrea
A
Bortolato
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Francesca
F
Deflorian
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Andrew S
AS
Doré
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
James C
JC
Errey
Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University P.O. Box 9502, 2300 RA Leiden, the Netherlands.
Laura H
LH
Heitman
Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University P.O. Box 9502, 2300 RA Leiden, the Netherlands.
Adriaan P
AP
IJzerman
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Fiona H
FH
Marshall
Heptares Therapeutics Ltd , Biopark Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
Robert M
RM
Cooke
D002478:Cells, Cultured; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D015202:Protein Engineering; D043705:Receptor, Adenosine A2A / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014227:Triazines / Q000737:chemistry* / Q000494:pharmacology*; D014230:Triazoles / Q000737:chemistry* / Q000494:pharmacology*
D008024:Ligands; D043705:Receptor, Adenosine A2A; D014227:Triazines; D014230:Triazoles; C097270:ZM 241385