Dual receptor-sites reveal the structural basis for hyperactivation of sodium channels by poison-dart toxin batrachotoxin

Autor: Lige Tonggu, Goragot Wisedchaisri, Tamer M. Gamal El-Din, Michael J. Lenaeus, Matthew M. Logan, Tatsuya Toma, Justin Du Bois, Ning Zheng, William A. Catterall
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Nature Communications, Vol 15, Iss 1, Pp 1-14 (2024)
Druh dokumentu: article
ISSN: 2041-1723
DOI: 10.1038/s41467-024-45958-w
Popis: 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.
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