Rucha Wadapurkar, Anil Kumar Katti
Abstract: Conotoxins are a group of cysteine-rich peptide-based toxins in the venom of cone snails. The small peptides of -Conotoxin Mr1.7a from Conus marmoreus behave pharmacologically as competitive antagonists of the nicotinic acetylcholine receptor nAChR 32. Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels, widely spread in the central and peripheral system. nAChRs modulate the release of neurotransmitters, such as dopamine, norepinephrine, acetylcholine and -amino butyric acid, and they are involved in a variety of pathophysiologies, including chronic pain syndromes, epilepsy, Parkinsons and Alzheimers. The physicochemical properties of the -Conotoxin Mr1.7a were analyzed by using ExPASy ProtParam tool. The secondary structure prediction was done by SOPMA which showed that alpha helix dominated all the other conformations. 3D structure was predicted using modeller and validated using PROCHECK with 83.9 % found in most favoured regions [A, B, L]. VaxiJen 2.0 server predicted -Conotoxin Mr1.7a as a non-antigenic. Binding sites were predicted using DoGSiteScorer. Docking of -Conotoxin Mr1.7a was performed against target neuronal nAChR 32 using Hex 6.3 tool. The docking result with Etotal of -598.19 was provided a reasonable structural basis that can be used for future investigations on nAChR-ligand complex and -Conotoxins serve as a best therapeutic agent.
Keywords: Conotoxin Mr17a, Conus marmoreus, nAChR 32, DoGSiteScorer, Hex