Homology model and targeted mutagenesis identify critical residues for arachidonic acid inhibition of Kv4 channels

作者: Robert Heler , Jessica K. Bell , Linda M. Boland

DOI: 10.4161/CHAN.23453

关键词: Peptide sequenceStereochemistryProtein subunitHomology modelingXenopusDocking (molecular)BiologyBinding siteLinkerArachidonic acid

摘要: Polyunsaturated fatty acids such as arachidonic acid (AA) exhibit inhibitory modulation of Kv4 potassium channels. Molecular docking approaches using a Kv4.2 homology model predicted membrane-embedded binding pocket for AA comprised the S4-S5 linker on one subunit and several hydrophobic residues within S3, S5 S6 from an adjacent subunit. The is conserved among We tested hypothesis that modulatory effects Kv4.2/KChIP channels require access to this site. Targeted mutation polar residue (K318) nonpolar (G314) well in S3 (V261) significantly impaired K+ currents Xenopus oocytes. These may be important stabilizing or regulating (V261, G314) negatively charged carboxylate moiety acid. Structural specificity was supported by lack disruption observed with mutations at located near, but not pocket. Furthermore, we found crystal structure related Kv1.2/2.1 chimera lacks structural features present proposed site were unaffected AA. simulated mutagenic substitutions our demonstrate how specific disrupt putative conclude inhibits channel facilitates current decay which K318 critical interaction.

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