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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/2312

Title: A novel scorpion toxin blocking small conductance Ca2+ activated K+ channel
Authors: XU, Chen-qi
He, LL
Martin-Eauclaire, MF
Chi, CW
Issue Date: 2004
Citation: TOXICON, 43(8). p. 961-971
Abstract: Small conductance calcium activated potassium channels (SK) are crucial in the regulation of cell firing frequency in the nervous system and other tissues. In the present work, a novel SK channel blocker, designated BmSKTx1, was purified from the scorpion Buthus martensi Karsh venom. The sequence of the N-terminal 22 amino acid residues was determined by Edman degradation. Using this sequence information, the full-length cDNA and genomic gene of BmSKTx1 were cloned and sequenced. By these analyses, BmSKTx1 was found to be a peptide composed of 31 amino acid residues with three disulfide bonds. It shared little sequence homology with other known scorpion alpha-KTxs but showed close relationship with SK channel blockers in the phylogenetic tree. According to the previous nomenclature, BmSKTx1 was classified as alpha-KTx14.1. We examined the effects of BmSKTx1 on different ion channels of rat adrenal chromaffin cells (RACC) and locust dorsal unpaired median (DUM) neurons. BmSKTx1 selectively inhibited apamin-sensitive SK currents in RACC with K-d of 0.72 p,M and Hill coefficient of 2.2. And it had no effect on Na+, Ca2+, Kv, and BK currents in DUM neuron, indicating that BmSKTx1 was a selective SK toxin. (C) 2004 Elsevier Ltd. All rights reserved.
Notes: Chinese Acad Sci, Key Lab Proteom, Inst Biochem & Cell Biol, Shanghai 200031, Peoples R China. Tongji Univ, Inst Prot Res, Shanghai 200092, Peoples R China. Chinese Acad Sci, Inst Neurosci, Shanghai 200031, Peoples R China. Limburgs Univ Ctr, Physiol Lab, B-3590 Diepenbeek, Belgium. Univ Mediterranee, IFR Jean Roche, Fac Med Nord, CNRS,UMR 6560,Lab Biochim, Marseille, France.Chi, CW, Chinese Acad Sci, Key Lab Proteom, Inst Biochem & Cell Biol, 320 Yue Yang Rd, Shanghai 200031, Peoples R China.chi@sunm.shcnc.ac.cn
URI: http://hdl.handle.net/1942/2312
DOI: 10.1016/j.toxicon.2004.01.018
ISI #: 000222564500012
ISSN: 0041-0101
Category: A1
Type: Journal Contribution
Validation: ecoom, 2005
Appears in Collections: Research publications

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