Comparative pharmacology and cloning of two novel arachnid sodium channels: Exploring the adaptive insensitivity of scorpion to its toxins.
Scorpion toxins have been found lacking effect on Na(+) current of its own sodium channel, whereas the molecular mechanism remains mystery. In this study, the binding affinity of pharmacologically distinct scorpion toxins was found much weaker to scorpion (Buthus martensii) nerve synaptosomes than to spider (Ornithoctonus huwena) ones. The sodium channel cDNA from these two species were further cloned. The deduced proteins contain 1871 and 1987 amino acids respectively. Several key amino acid substitutions, i.e., A1610V, I1611L and S1617K, are found in IVS3-S4 constituting receptor site-3, and for receptor site-4, two residues (Leu-Pro) are inserted near IIS4 of scorpion sodium channel.
Zuo
Xiao-Pan
XP
Graduate School of the Chinese Academy of Sciences, Shanghai Institute of Physiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, PR China.
He
Hui-Qiong
HQ
He
Ming
M
Liu
Zhi-Rui
ZR
Xu
Qing
Q
Ye
Jian-Guo
JG
Ji
Yong-Hua
YH
D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D012604:Scorpion Venoms / Q000378:metabolism*; D012605:Scorpions / Q000235:genetics; D016415:Sequence Alignment; D015222:Sodium Channels / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D013112:Spiders / Q000235:genetics; D013574:Synaptosomes / Q000378:metabolism
D012604:Scorpion Venoms; D015222:Sodium Channels