Molecular cloning and functional expression of a gene encoding an antiarrhythmia peptide derived from the scorpion toxin.
From a cDNA library of Chinese scorpion Buthus martensii Karsch, full-length cDNAs of 351 nucleotides encoding precursors (named BmKIM) that contain signal peptides of 21 amino acid residues, a mature toxin of 61 residues with four disulfide bridges, and an extra Gly-Lys-Lys tail, were isolated. The genomic sequence of BmKIM was cloned and sequenced; it consisted of two exons disrupted by an intron of 1622 bp, the largest known in scorpion toxin genomes, inserted in the region encoding the signal peptide. The cDNA was expressed in Escherichia coli. The recombinant BmKIM was toxic to both mammal and insects. This is the first report that a toxin with such high sequence homology with an insect-specific depressant toxin group exhibits toxicity to mammals. Using whole cell patch-clamp recording, it was discovered that the recombinant BmKIM inhibited the sodium current in rat dorsal root ganglion neurons and ventricular myocytes and protected against aconitine- induced cardiac arrhythmia.
Peng
Fang
F
Department of Biotechnology, College of Life Sciences, Wuhan University, China Department of Cardiology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China.
Zeng
Xian-Chun
XC
He
Xiao-Hua
XH
Pu
Jun
J
Li
Wen-Xin
WX
Zhu
Zhi-Hui
ZH
Liu
Hui
H
D000157:Aconitine / Q000378:metabolism; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy; D002942:Circular Dichroism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004926:Escherichia coli; D015723:Gene Library; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles; D008969:Molecular Sequence Data; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000494:pharmacology*; D012605:Scorpions / Q000235:genetics / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects* / Q000378:metabolism
D000889:Anti-Arrhythmia Agents; C467987:BmKIM peptide; D018076:DNA, Complementary; D010455:Peptides; D011993:Recombinant Fusion Proteins; D012604:Scorpion Venoms; D015222:Sodium Channels; D012964:Sodium; D000157:Aconitine