title: Tarantula toxins use common surfaces for interacting with Kv and ASIC ion channels.
abstract: Tarantula toxins that bind to voltage-sensing domains of voltage-activated ion channels are thought to partition into the membrane and bind to the channel within the bilayer. While no structures of a voltage-sensor toxin bound to a channel have been solved, a structural homolog, psalmotoxin (PcTx1), was recently crystalized in complex with the extracellular domain of an acid sensing ion channel (ASIC). In the present study we use spectroscopic, biophysical and computational approaches to compare membrane interaction properties and channel binding surfaces of PcTx1 with the voltage-sensor toxin guangxitoxin (GxTx-1E). Our results show that both types of tarantula toxins interact with membranes, but that voltage-sensor toxins partition deeper into the bilayer. In addition, our results suggest that tarantula toxins have evolved a similar concave surface for clamping onto α-helices that is effective in aqueous or lipidic physical environments.
authors.affiliation: Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, United States.
authors.forename: Kanchan
authors.initials: K
authors.lastname: Gupta
authors.affiliation: Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, United States.
authors.forename: Maryam
authors.initials: M
authors.lastname: Zamanian
authors.affiliation: Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, United States.
authors.forename: Chanhyung
authors.initials: C
authors.lastname: Bae
authors.affiliation: Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, United States.
authors.forename: Mirela
authors.initials: M
authors.lastname: Milescu
authors.affiliation: Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, United States.
authors.forename: Dmitriy
authors.initials: D
authors.lastname: Krepkiy
authors.affiliation: Department of Physiology and Membrane Biology, University of California, Davis, Davis, United States.
authors.forename: Drew C
authors.initials: DC
authors.lastname: Tilley
authors.affiliation: Department of Physiology and Membrane Biology, University of California, Davis, Davis, United States.
authors.forename: Jon T
authors.initials: JT
authors.lastname: Sack
authors.affiliation: Department of Physiology and Membrane Biology, University of California, Davis, Davis, United States.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Yarov-Yarovoy
authors.affiliation: Department of Life Science, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
authors.forename: Jae Il
authors.initials: JI
authors.lastname: Kim
authors.affiliation: Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, United States.
authors.forename: Kenton J
authors.initials: KJ
authors.lastname: Swartz
mesh_terms: D062646:Acid Sensing Ion Channel Blockers / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D062565:Acid Sensing Ion Channels / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D015870:Gene Expression; D015640:Ion Channel Gating; D007700:Kinetics; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D051669:Shab Potassium Channels / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D013111:Spider Venoms / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D013112:Spiders; D053835:Unilamellar Liposomes / Q000737:chemistry; D014982:Xenopus laevis
chemical_list: C568266:ASIC1 protein, human; D062646:Acid Sensing Ion Channel Blockers; D062565:Acid Sensing Ion Channels; D060829:Arthropod Proteins; C550903:GxTX-1E, Plesiophrictus guangxiensis; C496988:KCNB1 protein, human; D009498:Neurotoxins; C413209:PcTX1 protein, Psalmopoeus cambridgei; D010455:Peptides; D011993:Recombinant Fusion Proteins; D051669:Shab Potassium Channels; D013111:Spider Venoms; D053835:Unilamellar Liposomes
keywords: biophysics; oocytes; structural biology; tarantula; toxins; xenopus