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

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 A 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.
Mesh Terms:
Amino Acid Sequence, Binding Sites, Humans, Ion Channel Gating, Kv1.3 Potassium Channel, Membrane Potentials, Microscopy, Electron, Models, Molecular, Molecular Conformation, Potassium, Potassium Channels, Potassium Channels, Voltage-Gated, Sequence Alignment
Proc Natl Acad Sci U S A
Date: Dec. 01, 2021
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