Selective Inhibition of Rat α7 Nicotinic Acetylcholine Receptors by LvID, a Newly Characterized α4/7-Conotoxin from Conus lividus

The α7 nicotinic acetylcholine receptors (nAChRs), identified in peripheral and central nervous systems, are crucial for cognitive function, memory, inflammation, and are linked to disorders like Alzheimer's disease (AD), lung cancer, myasthenia gravis, and atherosclerosis. Here we report that a novel α4/7-conotoxin (CTx) LvID, from Conus lividus, potently inhibits rat α7 nAChRs expressed in Xenopus oocytes with an IC₅₀ of 13.8 nM, showing little activity against other rat nAChR subtypes. The structure of LvID was elucidated using nuclear magnetic resonance (NMR) spectroscopy and comprises a short helix braced by disulfide bonds. The key residues of LvID that bind to the α7 nAChRs were determined from a series of alanine mutants. Molecular simulation provided a possible explanation for the activity and specificity of LvID binding to α7 nAChRs. This finding offers a vital pharmacological tool for investigating the structural features and functional mechanisms of α7 nAChRs.