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| Item Type: | Article |
|---|---|
| Title: | Atomic structure and plasticity of the CTX-MthK complex investigated by cryo-EM, NMR, and MD simulations |
| Creators: |
Qoraj, Denis  ORCID: https://orcid.org/0009-0008-6944-4175, Mohr, Swantje, Aldakul, Yessenbek K ORCID: https://orcid.org/0000-0002-9686-9899, Sprink, Thiemo ORCID: https://orcid.org/0000-0002-0760-6828, Öster, Carl ORCID: https://orcid.org/0000-0002-8723-4533, Xiao, Taoran, Schmieder, Peter, Lange, Sascha, Utesch, Tillmann ORCID: https://orcid.org/0000-0002-3617-2002, Roderer, Daniel ORCID: https://orcid.org/0000-0002-7276-3467, Chen, Shanshuang ORCID: https://orcid.org/0000-0003-2317-6589, Sun, Han ORCID: https://orcid.org/0000-0002-1655-0838 and Lange, Adam ORCID: https://orcid.org/0000-0002-7534-5973
|
| Abstract: | Scorpion toxins block potassium channels, disrupting cellular excitability and causing symptoms such as pain, muscle spasms, or paralysis. Here, we use an integrated structural biology approach to uncover the binding mode of the scorpion toxin charybdotoxin (CTX) to the MthK channel, a model system for human large-conductance potassium (BK) channels. Cryo-EM defines the overall architecture of the MthK-CTX complex, while complementary solution- and solid-state NMR experiments identify key binding residues and show that toxin engagement alters the selectivity filter (SF) ion configuration without rearranging the filter itself. NMR and MD simulations further reveal an anchoring lysine residue stably inserted into the SF, while other contacts undergo fast NMR timescale dynamics. Together, these findings explain how CTX-like toxins maintain exceptionally high affinity while tolerating binding across multiple K⁺ channel subtypes, paving the way for site-specific extracellular modulation. |
| Keywords: | Binding Sites, Charybdotoxin, Cryoelectron Microscopy, Magnetic Resonance Spectroscopy, Molecular Dynamics Simulation, Potassium Channels, Protein Binding, Protein Conformation, Animals |
| Source: | Nature Communications |
| ISSN: | 2041-1723 |
| Publisher: | Nature Publishing Group |
| Volume: | 17 |
| Number: | 1 |
| Page Range: | 8724 |
| Date: | 20 August 2026 |
| Official Publication: | https://doi.org/10.1038/s41467-026-76925-2 |
| PubMed: | View item in PubMed |
| Related to: |
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