Sequence characterization of a novel alpha-neurotoxin from the king cobra (Ophiophagus hannah) venom.
Several postsynaptic neurotoxins (alpha-neurotoxins) with distinct pharmacological and biochemical properties were isolated and purified from the King cobra venom (Ophiophagus hannah) by employing sequentially preparative-scale cation-exchange chromatography on SP-Sephadex C-25 coupled with gel filtration and reversed-phase HPLC. The complete sequence of one neurotoxin was determined by N-terminal Edman degradation with the automatic pulsed-liquid phase sequencer on some peptide fragments generated from the endopeptidases, i.e. trypsin, S. aureus V8 protease and lysyl endopeptidase. This novel neurotoxin is a basic polypeptide of pI 9.05, consisting of 72 amino-acid residues with 10 cysteine residues. It is found to share about 60% sequence homology with Toxins a and b isolated from the same venom and the well established alpha-bungarotoxin, a major postsynaptic toxic ligand for acetylcholine receptor isolated from Bungarus multicinctus. The characterized alpha-neurotoxin molecules were also shown to bind specifically with nicotinic acetylcholine receptors of the electric eel, Torpedo californica.
Chang
C C
CC
Department of Biochemistry, Kaohsiung Medical College, Taiwan.
Huang
T Y
TY
Kuo
K W
KW
Chen
S W
SW
Huang
K F
KF
Chiou
S H
SH
D000595:Amino Acid Sequence; D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004546:Elapid Venoms / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D004557:Electric Organ / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010446:Peptide Fragments / Q000302:isolation & purification; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011978:Receptors, Nicotinic / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012911:Snakes; D014101:Torpedo
D004546:Elapid Venoms; D009498:Neurotoxins; D010446:Peptide Fragments; D011978:Receptors, Nicotinic; D010450:Endopeptidases