Molecular basis for pore blockade of human Na channel Na1.2 by the μ-conotoxin KIIIA.

TitleMolecular basis for pore blockade of human Na channel Na1.2 by the μ-conotoxin KIIIA.
Publication TypeJournal Article
Year of Publication2019
AuthorsPan, X, Li, Z, Huang, X, Huang, G, Gao, S, Shen, H, Liu, L, Lei, J, Yan, N
Date Published2019 Mar 22
KeywordsAmino Acid Sequence, Conotoxins, Cryoelectron Microscopy, HEK293 Cells, Humans, NAV1.2 Voltage-Gated Sodium Channel, Protein Conformation, Voltage-Gated Sodium Channel beta-2 Subunit, Voltage-Gated Sodium Channel Blockers

<p>The voltage-gated sodium channel Na1.2 is responsible for the initiation and propagation of action potentials in the central nervous system. We report the cryo-electron microscopy structure of human Na1.2 bound to a peptidic pore blocker, the μ-conotoxin KIIIA, in the presence of an auxiliary subunit, β2, to an overall resolution of 3.0 angstroms. The immunoglobulin domain of β2 interacts with the shoulder of the pore domain through a disulfide bond. The 16-residue KIIIA interacts with the extracellular segments in repeats I to III, placing Lys at the entrance to the selectivity filter. Many interacting residues are specific to Na1.2, revealing a molecular basis for KIIIA specificity. The structure establishes a framework for the rational design of subtype-specific blockers for Na channels.</p>

Alternate JournalScience
PubMed ID30765605