Residue Phe266 in S5-S6 loop is not critical for Charybdotoxin binding to Ca2+-activated K+ (mSlo1) channels.
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.
Yao
Jing
J
Institute of Biochemistry and Biophysics, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Li
Hui
H
Gan
Ge-liang
GL
Wu
Ying
Y
Ding
Jiu-ping
JP
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
C465449:Kcnma1 protein, mouse; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D009498:Neurotoxins; D018999:Charybdotoxin