Download MendeleyDual receptor-sites reveal the structural basis for hyperactivation of sodium channels by poison-dart toxin batrachotoxin.
Tonggu, L., Wisedchaisri, G., Gamal El-Din, T.M., Lenaeus, M.J., Logan, M.M., Toma, T., Du Bois, J., Zheng, N., Catterall, W.A.(2024) Nat Commun 15: 2306-2306
- PubMed: 38485923
- DOI: https://doi.org/10.1038/s41467-024-45958-w
- Primary Citation of Related Structures:
8T6L - PubMed Abstract:
The poison dart toxin batrachotoxin is exceptional for its high potency and toxicity, and for its multifaceted modification of the function of voltage-gated sodium channels. By using cryogenic electron microscopy, we identify two homologous, but nonidentical receptor sites that simultaneously bind two molecules of toxin, one at the interface between Domains I and IV, and the other at the interface between Domains III and IV of the cardiac sodium channel. Together, these two bound toxin molecules stabilize α/π helical conformation in the S6 segments that gate the pore, and one of the bound BTX-B molecules interacts with the crucial Lys1421 residue that is essential for sodium conductance and selectivity via an apparent water-bridged hydrogen bond. Overall, our structure provides insight into batrachotoxin's potency, efficacy, and multifaceted functional effects on voltage-gated sodium channels via a dual receptor site mechanism.
Organizational Affiliation:
Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA.
