Inhibition of Voltage-Gated K+ Channel Kv1.5 by Antiarrhythmic Drugs

Rong Chen, Shin Ho Chung*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    7 Citations (Scopus)

    Abstract

    Molecular dynamics simulations are employed to determine the inhibitory mechanisms of three drugs, 5-(4-phenoxybutoxy)psoralen (PAP-1), vernakalant, and flecainide, on the voltage-gated K+ channel Kv1.5, a target for the treatment of cardiac arrhythmia. At neutral pH, PAP-1 is neutral, whereas the other two molecules carry one positive charge. We show that PAP-1 forms stable dimers in water, primarily through hydrophobic interactions between aromatic rings. All three molecules bind to the cavity between the Ile508 and Val512 residues from the four subunits of the channel. Once bound, the drug molecules are flexible, with the average root-mean-square fluctuation being between 2 and 3 Å, which is larger than the radius of gyration of a bulky amino acid. The presence of a monomeric PAP-1 causes the permeating K+ ion to dehydrate, thereby creating a significant energy barrier. In contrast, vernakalant blocks the ion permeation primarily via an electrostatic mechanism and, therefore, must be in the protonated and charged form to be effective.

    Original languageEnglish
    Pages (from-to)2704-2710
    Number of pages7
    JournalBiochemistry
    Volume57
    Issue number18
    DOIs
    Publication statusPublished - 8 May 2018

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