title: Hanatoxin inserts into phospholipid membranes without pore formation.
abstract: Hanatoxin (HaTx), a 35-residue polypeptide from spider venom, functions as an inhibitor of Kv2.1 channels by interacting with phospholipids prior to affecting the voltage-sensor. However, how this water-soluble peptide modifies the gating remains poorly understood, as the voltage-sensor is deeply embedded within the bilayer. To determine how HaTx interacts with phospholipid bilayers, in this study, we examined the toxin-induced partitioning of liposomal membranes. HPLC-results from high-speed spin-down vesicles with HaTx demonstrated direct binding. Dynamic light scattering (DLS) and leakage assay results further indicated that neither membrane pores nor membrane fragmentations were observed in the presence of HaTx. To clarify the binding details, Langmuir trough experiments were performed with phospholipid monolayers by mimicking the external leaflet of membrane bilayers, indicating the involvement of acyl chains in such interactions between HaTx and phospholipids. Our current study thus describes the interaction pattern of HaTx with vesicle membranes, defining a membrane-partitioning mechanism for peptide insertion involving the membrane hydrocarbon core without pore formation.
authors.affiliation: Membrane Protein Research Core, Center for Biotechnology, National Taiwan University, Taipei 10672, Taiwan; Institute of Biotechnology, National Taiwan University, Taipei 10672, Taiwan. Electronic address: kllou@ntu.edu.tw.
authors.forename: Kuo-Long
authors.initials: KL
authors.lastname: Lou
authors.affiliation: Institute of Biotechnology, National Taiwan University, Taipei 10672, Taiwan.
authors.forename: Meng-Hsuan
authors.initials: MH
authors.lastname: Hsieh
authors.affiliation: Institute of Biotechnology, National Ilan University, Ilan 26047, Taiwan.
authors.forename: Wei-Jung
authors.initials: WJ
authors.lastname: Chen
authors.affiliation: Proteomics Lab, Cathay Medical Research Institute, Cathay General Hospital, Taipei 22174, Taiwan.
authors.forename: Yu-Che
authors.initials: YC
authors.lastname: Cheng
authors.affiliation: Membrane Protein Research Core, Center for Biotechnology, National Taiwan University, Taipei 10672, Taiwan.
authors.forename: Jia-Nan
authors.initials: JN
authors.lastname: Jian
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan; Department of Physics, National Central University, Jhongli 32001, Taiwan.
authors.forename: Ming-Tao
authors.initials: MT
authors.lastname: Lee
authors.affiliation: Department of System Engineering and Sciences, National Tsing-Hua University, HsinChu 30013, Taiwan.
authors.forename: Tsang-Lang
authors.initials: TL
authors.lastname: Lin
authors.affiliation: Membrane Protein Research Core, Center for Biotechnology, National Taiwan University, Taipei 10672, Taiwan.
authors.forename: Yu-Shuan
authors.initials: YS
authors.lastname: Shiau
authors.affiliation: Division of Neurology, National Taiwan University Hospital, Taipei 10002, Taiwan. Electronic address: hhl@ntu.edu.tw.
authors.forename: Horng-Huei
authors.initials: HH
authors.lastname: Liou
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D012542:Scattering, Radiation
chemical_list: D008051:Lipid Bilayers; D010455:Peptides; D010743:Phospholipids; C096469:hanatoxin; D015060:1,2-Dipalmitoylphosphatidylcholine
keywords: Hanatoxin; Liposomal vesicle membranes; Membrane partitioning; Peptide-lipid interactions; Transition temperature for phospholipids