title: Amiloride docking to acid-sensing ion channel-1.
abstract: Amiloride is a small molecule diuretic, which has been used to dissect sodium transport pathways in many different systems. This drug is known to interact with the epithelial sodium channel and acid-sensing ion channel proteins, as well as sodium/hydrogen antiporters and sodium/calcium exchangers. The exact structural basis for these interactions has not been elucidated as crystal structures of these proteins have been challenging to obtain, though some involved residues and domains have been mapped. This work examines the interaction of amiloride with acid-sensing ion channel-1, a protein whose structure is available using computational and experimental techniques. Using molecular docking software, amiloride and related molecules were docked to model structures of homomeric human ASIC-1 to generate potential interaction sites and predict which analogs would be more or less potent than amiloride. The predictions made were experimentally tested using whole-cell patch clamp. Drugs previously classified as NCX or NHE inhibitors are shown to also inhibit hASIC-1. Potential docking sites were re-examined against experimental data to remove spurious interaction sites. The voltage sensitivity of inhibitors was also examined. Using the aggregated data from these computational and experimental experiments, putative interaction sites for amiloride and hASIC-1 have been defined. Future work will experimentally verify these interaction sites, but at present this should allow for virtual screening of drug libraries at these putative interaction sites.
authors.affiliation: Departments of Physiology and Biophysics, Birmingham, Alabama 35294.
authors.forename: Yawar J
authors.initials: YJ
authors.lastname: Qadri
authors.affiliation: Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Song
authors.affiliation: Departments of Physiology and Biophysics, Birmingham, Alabama 35294.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Fuller
authors.affiliation: Departments of Physiology and Biophysics, Birmingham, Alabama 35294. Electronic address: benos@uab.edu.
authors.forename: Dale J
authors.initials: DJ
authors.lastname: Benos
mesh_terms: D062565:Acid Sensing Ion Channels; D000584:Amiloride / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002645:Chickens; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D020128:Inhibitory Concentration 50; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000737:chemistry* / Q000378:metabolism
chemical_list: C568266:ASIC1 protein, human; D062565:Acid Sensing Ion Channels; D009419:Nerve Tissue Proteins; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D000584:Amiloride