Two Potent α3/5 Conotoxins from Piscivorous Conus achatinus

作     者：Geoffrey CHEW Edward HAWROT 

作者机构：Department of Molecular Pharmacology Physiology and Biotechnology Brown University Providence Rhode Island 02903 USA 

出 版 物：《Acta Biochimica et Biophysica Sinica》 (生物化学与生物物理学报(英文版))

年 卷 期：2007年第39卷第6期

页      面：438-444页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 

基　　金：国家973计划 同济大学青年优秀人才培养行动计划项目 上海市曙光计划 美国国立卫生研究院(NIH)项目 

主　　题：cone snail α3/5 conotoxin disulfide bond nicotinic acetylcholine receptor 

摘      要：Every cone snail produces a mixture of different conotoxins and secretes them to immobilize their prey and predators. α3/5 Conotoxins, isolated from fish-hunting cone snails, target muscle nicotinic acetylcholine receptors. The structure and function of α3/5 conotoxin from the piscivorous Conus achatinus have not been studied. We synthesized two pentadecamer peptides, Ac 1.1 a and Ac 1.1 b, with appropriate disulfide bonding, based on cDNA sequences of α3/5 conotoxins from C. achatinus. Ac 1.1 a and Ac 1.1 b differ by only one amino acid residue. They have similar potency on blocking recombinant mouse muscle acetylcholine receptor expressed in Xenopus laevis oocytes, with IC50values of 36 nM and 26 nM, respectively. For Ac 1.1b, deletion of the first three N-terminal amino acids did not change its activity, indicating that the Nterminus is not involved in the interaction with its receptor. Furthermore, our experiments indicate that both toxins strongly prefer the α1-δ subunit interface instead of the α1-γ binding site on the mouse muscle nicotinic acetylcholine receptor. These peptides provide additional tools for the study of the structure and function of nicotinic receptor.