Molecular Basis for Ligand Modulation of a Mammalian Voltage-Gated Ca 2+ Channel

Cell. 2019 May 30;177(6):1495-1506.e12. doi: 10.1016/j.cell.2019.04.043.

Abstract

The L-type voltage-gated Ca2+ (Cav) channels are modulated by various compounds exemplified by 1,4-dihydropyridines (DHP), benzothiazepines (BTZ), and phenylalkylamines (PAA), many of which have been used for characterizing channel properties and for treatment of hypertension and other disorders. Here, we report the cryoelectron microscopy (cryo-EM) structures of Cav1.1 in complex with archetypal antagonistic drugs, nifedipine, diltiazem, and verapamil, at resolutions of 2.9 Å, 3.0 Å, and 2.7 Å, respectively, and with a DHP agonist Bay K 8644 at 2.8 Å. Diltiazem and verapamil traverse the central cavity of the pore domain, directly blocking ion permeation. Although nifedipine and Bay K 8644 occupy the same fenestration site at the interface of repeats III and IV, the coordination details support previous functional observations that Bay K 8644 is less favored in the inactivated state. These structures elucidate the modes of action of different Cav ligands and establish a framework for structure-guided drug discovery.

Keywords: Bay K 8644; Ca(v) 1.1; Ca(v) agonist; Ca(v) antagonist; cryo-EM structure; dihydropyridine; diltiazem; nifedipine; verapamil; voltage-gated calcium channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Calcium Channel Blockers / metabolism*
  • Calcium Channels / metabolism
  • Calcium Channels / physiology
  • Calcium Channels / ultrastructure
  • Calcium Channels, L-Type / metabolism*
  • Calcium Channels, L-Type / physiology
  • Calcium Channels, L-Type / ultrastructure*
  • Cryoelectron Microscopy
  • Diltiazem
  • Ligands
  • Male
  • Models, Molecular
  • Nifedipine
  • Rabbits
  • Verapamil

Substances

  • Calcium Channel Blockers
  • Calcium Channels
  • Calcium Channels, L-Type
  • Ligands
  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
  • Verapamil
  • Diltiazem
  • Nifedipine