Comparative study of three short-chain neurotoxins from the venom of Naja kaouthia (Yunnan, China).
Three short-chain neurotoxins named NT-1, NT-II, and NT-III were purified from the venom of Naja kaouthia, a snake distributed throughout the south of Yunnan province, China, by a series of chromatographic steps, including an FPLC Resource S column. Their molecular weights, determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS, were 6952.19 Da, 6854.92 Da, and 6828.80 Da, respectively. NT-I consisted of 62 amino acid residues, and the other two consisted of 61 amino acid residues, including 8 cysteines. After hydrolysis by endoproteinase Glu-C, their primary sequences were determined. A test of their activities demonstrated that they effectively inhibited muscle contractions induced by electric stimulation. Furthermore, the extent of inhibition caused by NT-II and NT-III was less than that of NT-I. The IC50s were 0.04 microg/ml, 0.20 microg/ml, and 0.23 microg/ml for NT-I, NT-II, and NT-III, respectively. Compared with NT-II and NT-III, the higher activity of NT-I may be a result of the amino acid residue substitution Ile36 to Arg36.
Department of Animal Toxicology, Kunming Institute of Zoology, Chinese Academy of Sciences, Yunnan, China.
Lu
L
Qiumin
Meng
M
Qingxiong
Li
L
Dongsheng
Zhu
Z
Shaowen
Jia
J
Yonghong
Xiong
X
Yuliang
Wang
W
Wanyu
D000595:Amino Acid Sequence; D000818:Animals; D004546:Elapid Venoms / Q000009:adverse effects* / Q000737:chemistry*; D017815:Elapidae; D004558:Electric Stimulation; D005260:Female; D007928:Lethal Dose 50; D008297:Male; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009498:Neurotoxins / Q000009:adverse effects* / Q000737:chemistry*; D051381:Rats
D004546:Elapid Venoms; D009498:Neurotoxins