PMID: 30765605

Authors:

Pan X, Li Z, Huang X, Huang G, Gao S, Shen H, Liu L, Lei J, Yan N

Title:

Molecular basis for pore blockade of human Na(+) channel Nav1.2 by the mu-conotoxin KIIIA.

Journal:

Science. 2019 Feb 14. pii: science.aaw2999. doi: 10.1126/science.aaw2999.

Abstract:

The voltage-gated sodium channel Nav1.2 is responsible for the initiation and propagation of action potentials in the central nervous system. We report the cryo-electron microscopy structure of human Nav1.2 bound to a peptidic pore blocker, the mu-conotoxin KIIIA, in the presence of an auxiliary subunit beta2 to an overall resolution of 3.0 A. The immunoglobulin (Ig) domain of beta2 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 Lys7 at the entrance to the selectivity filter. Many interacting residues are specific to Nav1.2, revealing a molecular basis for KIIIA specificity. The structure establishes a framework for rational design of subtype-specific blockers for Nav channels.