Differential Inhibition by Cenobamate of Canonical Human Nav1.5 Ion Channels and Several Point Mutants

Figures

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  Figure 1. Human Nav1.5 model in open conformation generated by AlphaFold 2 (represented as cartoon and colored in a red to blue colorscale according to the order of amino acids in the sequence) inserted in a DPPC bilayer (represented as licorice with atoms colored according to type): (a) top view, showing the channel in the middle of the lipid bilayer; (b) side view; (c) the file of alternating Na+ ions (blue sheres) and water molecules (red and white spheres) placed in the selectivity filter; the residues of the inner charge ring are highlighted and marked.

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  Figure 2. Cenobamate location in the central cavity of energy-optimized and equilibrated Nav1.5 model: (a) general view: cenobamate is represented as van der Waals spheres colored according to atom types and the protein is represented as cartoon colored in cyan; (b) detailed view of residues located at a distance of less than 4 Å (yellow licorice with labels, while all the protein is represented as green catoon) from the docked cenobamate molecule (red licorice); (c) a 2D interaction map between cenobamate and surrounding residues from wild-type Nav1.5 structure in which van der Waals interactions are represented in light green, conventional hydrogen bonds are represented in green, the unfavorable donor-donor interaction is shown in red and the pi-alkyl interaction is shown in pink; (d) representation of the surface of cenobamate binding site colored according to the hydrophobicity according to the blue to brown colorscale shown in lower left and cenobamate shown as licorice in the center of the site. Residues Leu1462, Asn932, and Asn927 are represented as licorice, and the interactions established with cenobamate are shown as dashed lines colored according to type (pi-alkyl is pink,…

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  Figure 3. Time series of the RMSD values across a 100 ns simulation, showing the relative stability of the mutant proteins.

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  Figure 4. RMSF values of channel protein residues across the 100 ns simulation for the wild-type Nav1.5 model. The transmembrane regions of the four domains (repeats I–IV) are marked and labeled in the figure with red.

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  Figure 5. RMSD time series of cenobamate molecules in the systems comprising wild-type and mutant Nav1.5 models calculated over 100 ns, showing how interactions with different receptor residues affect the movements of the ligand.

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  Figure 6. Propagation of AP wavefront along the string of 50 ventricular cardiomyocytes for a cenobamate concentration of 17 µM and an intermyocyte gap junctions coupling conductance Gj = 1000 pS/pF for different Nav1.5 variants: (a) wild-type Nav1.5; (b) mutant N1463K (rs1064795922); (c) mutant N1463Y (rs199473614); (d) mutant M1766R (rs752476527); cv—conduction velocity. Each color corresponds to APs generated by a cell in the 50-cell string, in rainbow order. The initial black lines correspond to the moment of current injection. The propagation times are shown in each image and the delays between APs are marked with arrows.