Referenced in: none

Automatically associated channels: SK2

Title: Structure-function relationship of bifunctional scorpion toxin BmBKTx1.

Authors: Suming Wang, Lijun Huang, Dieter Wicher, Chengwu Chi, Chenqi Xu

Journal, date & volume: Acta Biochim. Biophys. Sin. (Shanghai), 2008 Nov , 40, 955-63

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18989577

Abstract
As the first identified scorpion toxin active on both big conductance Ca2+-activated K+ channels (BK) and small conductance Ca2+-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 beta-sheet.