Structure-function relationship of bifunctional scorpion toxin BmBKTxl

• 来源期刊: 生物化学与生物物理学报（英文版）
• 关键词: BmBKTxl scorpion K+ channel toxin(KTx) K+ channel two functional faces
• 年，卷（期）: 2008,（11）
• 页码范围: 955-963
• 页数: 9页
• 语种: 英文
• DOI: 10.1111/j.1745-7270.2008.00479.x

摘要

As the first identified scorpion toxin active on both big conductance Ca2+-activated K+ channels (BK) and small conductance Ca2+-activated K+ channels (SK), BmBKTxl has been proposed to have two separate functional faces for two targets. To investigate this hypothesis, two double mutants,K21A-Y30A and R9A-KIlA, 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-KI1A 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.