The type 2 bradykinin receptor (B2R) is a G protein-coupled receptor (GPCR) in the cardiovascular system, and the dysfunction of B2R leads to inflammation, hereditary angioedema, and pain. Bradykinin and kallidin are both endogenous peptide agonists of B2R, acting as vasodilators to protect the cardiovascular system. Here we determine two cryo-electron microscopy (cryo-EM) structures of human B2R-G q in complex with bradykinin and kallidin at 3.0 Å and 2.9 Å resolution, respectively. The ligand-binding pocket accommodates S-shaped peptides, with aspartic acids and glutamates as an anion trap. The phenylalanines at the tail of the peptides induce significant conformational changes in the toggle switch W283 6.48 , the conserved PIF, DRY, and NPxxY motifs, for the B2R activation. This further induces the extensive interactions of the intracellular loops ICL2/3 and helix 8 with G q proteins. Our structures elucidate the molecular mechanisms for the ligand binding, receptor activation, and G q proteins coupling of B2R. Type 2 bradykinin receptor (B2R) is essential in vasodilation and cardioprotection. Here the authors present two cryo-EM structures of human B2R-Gq in complex with bradykinin and kallidin to elucidate the mechanisms for ligand binding, receptor activation, and Gq proteins coupling.
【저자키워드】 Cryoelectron microscopy, G protein-coupled receptors, Receptor pharmacology, 【초록키워드】 Structure, Inflammation, peptide, Cryo-electron microscopy, Proteins, cardiovascular system, molecular mechanism, Protein, Pain, peptides, cryo-EM, receptor, mechanism, Glutamate, binding, Ligand, Interaction, motifs, conformational change, dysfunction, Activation, G protein-coupled receptor, complex, agonist, cryo-EM structure, PROTECT, conserved, determine, induce, Type, acting, 【제목키워드】 Structure, Protein, complexes,