Two for the Price of One: Heterobivalent Ligand Design Targeting Two Binding Sites on Voltage-Gated Sodium Channels Slows Ligand Dissociation and Enhances Potency

• Published in: Journal of medicinal chemistry 2020-11, Vol.63 (21), p.12773-12785
• Main Authors: Peschel, Alicia, Cardoso, Fernanda C, Walker, Andrew A, Durek, Thomas, Stone, M. Rhia L, Braga Emidio, Nayara, Dawson, Philip E, Muttenthaler, Markus, King, Glenn F
• Format: Article
• Language: English
• Subjects: Action Potentials - drug effects; Amino Acid Sequence; Animals; Binding Sites; Conotoxins - chemistry; Conotoxins - metabolism; Cycloaddition Reaction; Humans; Inhibitory Concentration 50; Kinetics; Ligands; Molecular Docking Simulation; NAV1.4 Voltage-Gated Sodium Channel - chemistry; NAV1.4 Voltage-Gated Sodium Channel - metabolism; NAV1.7 Voltage-Gated Sodium Channel - chemistry; NAV1.7 Voltage-Gated Sodium Channel - metabolism; Patch-Clamp Techniques; Polyethylenes - chemistry; Spider Venoms - chemical synthesis; Spider Venoms - chemistry; Spider Venoms - metabolism; Spiders - metabolism; Voltage-Gated Sodium Channel Blockers - chemical synthesis; Voltage-Gated Sodium Channel Blockers - chemistry; Voltage-Gated Sodium Channel Blockers - metabolism; Voltage-Gated Sodium Channel Blockers - pharmacology
• ISSN: 0022-2623; 1520-4804
• DOI: 10.1021/acs.jmedchem.0c01107

Voltage-gated sodium (NaV) channels are pore-forming transmembrane proteins that play essential roles in excitable cells, and they are key targets for antiepileptic, antiarrhythmic, and analgesic drugs. We implemented a heterobivalent design strategy to modulate the potency, selectivity, and binding kinetics of NaV channel ligands. We conjugated μ-conotoxin KIIIA, which occludes the pore of the NaV channels, to an analogue of huwentoxin-IV, a spider-venom peptide that allosterically modulates channel gating. Bioorthogonal hydrazide and copper-assisted azide–alkyne cycloaddition conjugation chemistries were employed to generate heterobivalent ligands using polyethylene glycol linkers spanning 40–120 Å. The ligand with an 80 Å linker had the most pronounced bivalent effects, with a significantly slower dissociation rate and 4–24-fold higher potency compared to those of the monovalent peptides for the human NaV1.4 channel. This study highlights the power of heterobivalent ligand design and expands the repertoire of pharmacological probes for exploring the function of NaV channels.