Cloning and characterization of BmK86, a novel K+ -channel blocker from scorpion venom.
Scorpion venom represents a tremendous hitherto unexplored resource for understanding ion channels. BmK86 is a novel K+ -channel toxin gene isolated from a cDNA library of Mesobuthus martensii Karsch, which encodes a signal peptide of 22 amino acid residues and a mature toxin of 35 residues with three disulfide bridges. The genomic sequence of BmK86 consists of two exons disrupted by an intron of 72 bp. Comparison with the other scorpion toxins BmK86 shows low sequence similarity. The GST-BmK86 fusion protein was successfully expressed in Escherichia coli. The fusion protein was cleaved by enterokinase and the recombinant BmK86 was purified by HPLC. Using whole-cell patch-clamp recording, the recombinant BmK86 was found to inhibit the potassium current of mKv1.3 channel expressed in COS7 cells. These results indicated that BmK86 belongs to a representative member of a novel subfamily of alpha-KTxs. The systematic number assigned to BmK86 is alpha-KTx26.1.
Mao
Xin
X
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China.
Cao
Zhijian
Z
Yin
Shijin
S
Ma
Yibao
Y
Wu
Yingliang
Y
Li
Wenxin
W
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D026902:Potassium Channel Blockers / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012604:Scorpion Venoms / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D026902:Potassium Channel Blockers; D011994:Recombinant Proteins; D012604:Scorpion Venoms