Open AccessStructure‐function relationship of bifunctional scorpion toxin BmBKTx1
Author(s) -
Wang Suming,
Huang Lijun,
Wicher Dieter,
Chi Chengwu,
Xu Chenqi
Publication year - 2008
Publication title -
acta biochimica et biophysica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.771
H-Index - 57
eISSN - 1745-7270
pISSN - 1672-9145
DOI - 10.1111/j.1745-7270.2008.00479.x
Subject(s) - scorpion toxin , mutant , bk channel , toxin , escherichia coli , wild type , conductance , chemistry , biology , scorpion , biophysics , genetics , venom , potassium channel , biochemistry , gene , physics , condensed matter physics
As the first identified scorpion toxin active on both big conductance Ca 2+ ‐activated K + channels (BK) and small c on duc t a n c e Ca 2+ ‐activated K + channels (SK), BmBKTx1 has been proposed to have two separate functional faces for two targets. To investigate this hypothesis, two double mutants, K21A‐Y30A and R9A‐K11A, together with wild‐type toxin were expressed in Escherichia coli. The recombinant toxins were tested on cockroach BK and rat SK2 channel for functional assay. Mutant K21A‐Y30A had a dramatic loss of function on BK but retained its function on SK. Mutant R9A‐K11A did not lose function on BK or SK. These data support the two functional‐face hypothesis and indicate that the BK face is on the C‐terminal β‐sheet.