A novel alpha 4/7-conotoxin LvIA from Conus lividus that selectively blocks alpha 3 beta 2 vs. alpha 6/alpha 3 beta 2 beta 3 nicotinic acetylcholine receptors

作者：Luo, Sulan^*; Zhangsun, Dongting; Schroeder, Christina I.; Zhu, Xiaopeng; Hu, Yuanyan; Wu, Yong; Weltzin, Maegan M.; Eberhard, Spencer; Kaas, Quentin; Craik, David J.; McIntosh, J. Michael; Whiteaker, Paul

来源：The FASEB Journal, 2014, 28(4): 1842-1853.

DOI：10.1096/fj.13-244103

• nuclear magnetic resonance spectroscopy
• cholinergic
• ligand-gated ion channel receptor
• molecular modeling

This study was performed to discover and characterize the first potent alpha 3 beta 2-subtype-selective nicotinic acetylcholine receptor (nAChR) ligand. A novel alpha 4/7-conotoxin, alpha-CTxLvIA, was cloned from Conus lividus. Its pharmacological profile at Xenopus laevis oocyte-expressed rat nAChR subtypes was determined by 2-electrode voltage-clamp electrophysiology, and its 3-dimensional (3D) structure was determined by NMR spectroscopy. alpha-CTx LvIA is a 16-aa C-terminally-amidated peptide with 2-disulfide bridges. Using rat subunits expressed in Xenopus oocytes, we found the highest affinity of alpha-CTxLvIA was for alpha 3 beta 2 nAChRs (IC50 8.7 nM), where blockade was reversible within 2 min. IC50 values were > 100 nM at alpha 6/alpha 3 beta 2 beta 3, alpha 6/alpha 3 beta 4, and alpha 3 beta 4 nAChRs, and >= 3 mu M at all other subtypes tested. alpha 3 beta 2 vs. alpha 6 beta 2 subtype selectivity was confirmed for human-subunit nAChRs with much greater preference (300-fold) for alpha 3 beta 2 over alpha 6 beta 2 nAChRs. This is the first alpha-CTx reported to show high selectivity for human alpha 3 beta 2 vs. alpha 6 beta 2 nAChRs. alpha-CTxLvIA adopts two similarly populated conformations water: one (assumed to be bioactive) is highly structured, whereas the other is mostly random coil in nature. Selectivity differences with the similarly potent, but less selective, alpha 3 beta 2 nAChR antagonist alpha-CTx PeIA probably reside within the three residues, which differ in loop 2, given their otherwise similar 3D structures. alpha 4/7-CTx LvIA is a new, potent, selective alpha 3 beta 2 nAChR antagonist, which will enable detailed studies of alpha 3 beta 2 nAChR structure, function, and physiological roles.-Luo, S., Zhangsun, D., Schroeder, C. I., Zhu, X., Hu, Y., Wu, Y., Weltzin, M. M., Eberhard, S., Kaas, Q., Craik, D. J., McIntosh, J. M., Whiteaker, P. A novel alpha 4/7-conotoxin LvIA from Conus lividus that selectively blocks alpha 3 beta 2 vs. alpha 6/alpha 3 beta 2 beta 3 nicotinic acetylcholine receptors.

• 出版日期2014-4
• 单位海南大学