Resin-acid derivatives bind to multiple sites on the voltage-sensor domain of the Shaker potassium channel Show others and affiliations
2021 (English) In: The Journal of General Physiology, ISSN 0022-1295, E-ISSN 1540-7748, Vol. 153, no 4, article id e202012676Article in journal (Refereed) Published
Abstract [en]
Voltage-gated potassium (K-V) channels can be opened by negatively charged resin acids and their derivatives. These resin acids have been proposed to attract the positively charged voltage-sensor helix (S4) toward the extracellular side of the membrane by binding to a pocket located between the lipid-facing extracellular ends of the transmembrane segments S3 and S4. By contrast to this proposed mechanism, neutralization of the top gating charge of the Shaker KV channel increased resin-acid-induced opening, suggesting other mechanisms and sites of action. Here, we explore the binding of two resin-acid derivatives, Wu50 and Wu161, to the activated/open state of the Shaker KV channel by a combination of in silico docking, molecular dynamics simulations, and electrophysiology of mutated channels. We identified three potential resin-acid-binding sites around S4: (1) the S3/S4 site previously suggested, in which positively charged residues introduced at the top of S4 are critical to keep the compound bound, (2) a site in the cleft between S4 and the pore domain (S4/pore site), in which a tryptophan at the top of S6 and the top gating charge of S4 keeps the compound bound, and (3) a site located on the extracellular side of the voltage-sensor domain, in a cleft formed by S1-S4 (the top-VSD site). The multiple binding sites around S4 and the anticipated helical-screw motion of the helix during activation make the effect of resin-acid derivatives on channel function intricate. The propensity of a specific resin acid to activate and open a voltage-gated channel likely depends on its exact binding dynamics and the types of interactions it can form with the protein in a state-specific manner.
Place, publisher, year, edition, pages ROCKEFELLER UNIV PRESS , 2021. Vol. 153, no 4, article id e202012676
National Category
Pharmacology and Toxicology
Identifiers URN: urn:nbn:se:liu:diva-174771 DOI: 10.1085/jgp.202012676 ISI: 000630187200001 PubMedID: 33683319 OAI: oai:DiVA.org:liu-174771 DiVA, id: diva2:1541711
Note Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [20180404, 2018-04905]; Gustafsson Foundation, and Science for Life Laboratory; Swedish Brain Foundation [FO2019-0247]; Swedish Heart-Lung FoundationSwedish Heart-Lung Foundation [20180404]
2021-04-012021-04-012024-03-22 Bibliographically approved