title: Residue Phe266 in S5-S6 loop is not critical for Charybdotoxin binding to Ca2+-activated K+ (mSlo1) channels.
abstract: OBJECTIVE
  To gain insight into the interaction between the Charybdotoxin (ChTX) and BK channels.
  
  
  METHODS
  Site-directed mutagenesis was used to make two mutants: mSlo1-F266L and mSlo1-F266A. The two mutants were then expressed in Xenopus oocytes and their effects were tested on ChTX by electrophysiology experiments.
  
  
  RESULTS
  We demonstrate an equilibrium dissociation constant Kd=3.1-4.2 nmol/L for both the mutants mSlo1-F266L and mSlo1-F266A similar to that of the wild-type mSlo1 Kd=3.9 nmol/L.
  
  
  CONCLUSIONS
  The residue Phe266 does not play a crucial role in binding to ChTX, which is opposed to the result arising from the simulation of peptide-channel interaction.
authors.affiliation: Institute of Biochemistry and Biophysics, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yao
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Ge-liang
authors.initials: GL
authors.lastname: Gan
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Jiu-ping
authors.initials: JP
authors.lastname: Ding
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018999:Charybdotoxin / Q000494:pharmacology*; D005260:Female; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009498:Neurotoxins / Q000494:pharmacology*; D009865:Oocytes / Q000378:metabolism* / Q000502:physiology; D011485:Protein Binding / Q000187:drug effects; D014982:Xenopus laevis
chemical_list: C465449:Kcnma1 protein, mouse; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D009498:Neurotoxins; D018999:Charybdotoxin