Rearrangement of a unique Kv1.3 selectivity filter conformation upon binding of a drug

Anu Tyagi, Tofayel Ahmed, Shi Jian, Saumya Bajaj, Seow Theng Ong, Stephanie Shee Min Goay, Yue Zhao, Igor Vorobyov, Changlin Tian, K. George Chandy, Shashi Bhushan

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We report two structures of the human voltage-gated potassium channel (Kv) Kv1.3 in immune cells alone (apo-Kv1.3) and bound to an immunomodulatory drug called dalazatide (dalazatide–Kv1.3). Both the apo-Kv1.3 and dalazatide–Kv1.3 structures are in an activated state based on their depolarized voltage sensor and open inner gate. In apo-Kv1.3, the aromatic residue in the signature sequence (Y447) adopts a position that diverges 11 Å from other K+ channels. The outer pore is significantly rearranged, causing widening of the selectivity filter and perturbation of ion binding within the filter. This conformation is stabilized by a network of intrasubunit hydrogen bonds. In dalazatide–Kv1.3, binding of dalazatide to the channel’s outer vestibule narrows the selectivity filter, Y447 occupies a position seen in other K+ channels, and this conformation is stabilized by a network of intersubunit hydrogen bonds. These remarkable rearrangements in the selectivity filter underlie Kv1.3’s transition into the drug-blocked state.

Original languageEnglish (US)
Article numbere2113536119
JournalProceedings of the National Academy of Sciences of the United States of America
Volume119
Issue number5
DOIs
StatePublished - Feb 1 2022

Keywords

  • Dalazatide
  • Ion channels
  • Potassium channels
  • Selectivity filter
  • ShK

ASJC Scopus subject areas

  • General

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