28no | pdb_000028no

CTX/MthK complex

spinqualitylabelsall models 28no, resolution 4.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 28no is a 5 chain structure with sequence from Leiurus hebraeus and Methanothermobacter thermautotrophicus str. Delta H. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 4.1Å Ligands: K, PCA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed 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. Atomic structure and plasticity of the CTX-MthK complex investigated by cryo-EM, NMR, and MD simulations.,Qoraj D, Mohr S, Aldakul YK, Sprink T, Oster C, Xiao T, Schmieder P, Lange S, Utesch T, Roderer D, Chen S, Sun H, Lange A Nat Commun. 2026 Aug 20;17(1):8724. doi: 10.1038/s41467-026-76925-2. PMID:42624849 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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