Psalmotoxin-1 docking to human acid-sensing ion channel-1.
Acid-sensing ion channel-1 (ASIC-1) is a proton-gated ion channel implicated in nociception and neuronal death during ischemia. Recently the first crystal structure of a chicken ASIC was obtained. Expanding upon this work, homology models of the human ASICs were constructed and evaluated. Energy-minimized structures were tested for validity by in silico docking of the models to psalmotoxin-1, which potently inhibits ASIC-1 and not other members of the family. The data are consistent with prior radioligand binding and functional assays while also explaining the selectivity of PcTX-1 for homomeric hASIC-1a. Binding energy calculations suggest that the toxin and channel create a complex that is more stable than the channel alone. The binding is dominated by the coulombic contributions, which account for why the toxin-channel interaction is not observed at low pH. The computational data were experimentally verified with single channel and whole-cell electrophysiological studies. These validated models should allow for the rational design of specific and potent peptidomimetic compounds that may be useful for the treatment of pain or ischemic stroke.
Qadri
Yawar J
YJ
Department of Physiology and Biophysics, University of Alabama, Birmingham, AL 35294, USA.
Berdiev
Bakhrom K
BK
Song
Yuhua
Y
Lippton
Howard L
HL
Fuller
Catherine M
CM
Benos
Dale J
DJ
D062565:Acid Sensing Ion Channels; D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004594:Electrophysiology; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010455:Peptides; D011487:Protein Conformation; D015222:Sodium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013111:Spider Venoms / Q000378:metabolism*
C568266:ASIC1 protein, human; D062565:Acid Sensing Ion Channels; D009419:Nerve Tissue Proteins; C413209:PcTX1 protein, Psalmopoeus cambridgei; D010455:Peptides; D015222:Sodium Channels; D013111:Spider Venoms