Lys39-Lysophosphatidate Carbonyl Oxygen Interaction Locks LPA1 N-terminal Cap to the Orthosteric Site and partners Arg124 During Receptor Activation.
Lysophosphatidic acid (LPA) receptor 1 (LPA1) is a member of the G protein-coupled receptors mediating the biological response to LPA species. Lack of detailed mechanism underlying LPA/LPA1 interaction has hampered the development of specific antagonists. Here, novel N-terminal Lys39 has been identified as a key residue during LPA-type agonist binding and LPA1 activation. Analysis of the molecular dynamics (MD) trajectories showed that LPA-type agonist but not VPC-32183 (antagonist) evolved structures with classical GPCR activation signatures such as reduced cytoplasmic transmembrane (TM) 3/TM6 dynamic network, ruptured ionic lock, and formation of a continuous and highly ordered internal water pathway was also observed. In activated state, LPA-type agonists interact with Arg124 (R3.28), Gln125 (Q3.29), Lys294 (K7.36) and a novel N-terminal Lys39. Site-directed mutagenesis showed complete loss of intracellular calcium mobilization in B103 cells expressing R3.28A and Lys39Ala when treated with LPA-type agonists. Structurally, LPA-type agonist via Carbonyl-oxygen/Lys39 interaction facilitated the formation of a hypothetical N-terminal cap tightly packed over LPA1 heptahelical bundle. This packing may represent a key mechanism to distinguish an apo-receptor from bound LPA1.
1] From the Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Japan [2] From the Center for Drug Discovery and Therapeutic Innovation, Nagasaki University, Japan.
Olaposi I
OI
Omotuyi
From the Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Japan.
Jun
J
Nagai
1] From the Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Japan [2] From the Center for Drug Discovery and Therapeutic Innovation, Nagasaki University, Japan.
Hiroshi
H
Ueda
D019943:Amino Acid Substitution; D000818:Animals; D001120:Arginine / Q000737:chemistry; D001665:Binding Sites; D020013:Calcium Signaling; D045744:Cell Line, Tumor; D006801:Humans; D008239:Lysine / Q000737:chemistry; D008246:Lysophospholipids / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D010100:Oxygen / Q000737:chemistry; D017434:Protein Structure, Tertiary; D051381:Rats; D049368:Receptors, Lysophosphatidic Acid / Q000819:agonists / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D008246:Lysophospholipids; D049368:Receptors, Lysophosphatidic Acid; D001120:Arginine; D008239:Lysine; C032881:lysophosphatidic acid; D010100:Oxygen