A novel α4/7‐conotoxin LvIA from Conus lividus that selectively blocks α3β2 vs. α6/α3β2β3 nicotinic acetylcholine receptors. Issue 4 (7th January 2014)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: FASEB journal. Volume 28:Issue 4(2014)
• Page Start: 1842
• Page End: 1853
• Publication Date: 2014-01-07
• Subjects: ligand‐gated ion channel receptor -- cholinergic -- nuclear magnetic resonance spectroscopy -- molecular modeling; Biology -- Periodicals; Biology, Experimental -- Periodicals; 570
• DOI: 10.1096/fj.13-244103
• Languages: English
• ISSNs: 0892-6638

Abstract

Abstract : This study was performed to discover and characterize the first potent α3β2‐subtype‐selective nicotinic acetylcholine receptor (nAChR) ligand. A novel α4/7‐conotoxin, α‐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. α‐CTx LvIA is a 16‐aa C‐terminallyamidated peptide with 2‐disulfide bridges. Using rat subunits expressed in Xenopus oocytes, we found the highest affinity of α‐CTxLvIA was for α3β2 nAChRs (IC50 8.7 nM), where blockade was reversible within 2 min. IC50 values were >100 nM at α6/α3β2β3, α6/α3β4, and α3β4 nAChRs, and ≥3 μM at all other subtypes tested. α3β2 vs. α6β2 subtype selectivity was confirmed for human‐subunit nAChRs with much greater preference (300‐fold) for α3β2 over α6β2 nAChRs. This is the first α‐CTx reported to show high selectivity for human α3β2 vs. α6β2 nAChRs. α‐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, α3β2 nAChR antagonist α‐CTx PeIA probably reside within the three residues, which differ in loop 2, given their otherwise similar 3D structures. α4/7‐CTx LvIA is a new, potent, selective α3β2 nAChR antagonist, which will enable detailed studies of α3β2 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 α4/7‐conotoxin LvIA from Conus lividus that selectively blocks α3β2 vs. α6/α3β2β3 nicotinic acetylcholine receptors. FASEB J. 28, 1842–1853 (2014). www.fasebj.org