Structural optimization and docking studies of anatoxin-a: A potent neurotoxin

In this investigation, our aim was to get more insight on the geometry optimization, structural properties and molecular interaction of anatoxin-a, a naturally occurring potent neurotoxin. The geometry of the anatoxin-a was fully optimized in terms of density functional theory Gaussian 09. Calculations for structural parameters viz. total energy, dipole moment, electro-negativity, chemical hardness, chemical softness, electronic chemical potential and electrophilic index of optimized geometries has been carried out. The energy difference between HOMO-LUMO was found to be -4.89 eV. Furthermore, the molecular docking of anatoxin-a with nicotinic acetylcholine receptor (nAChR) was performed in order to find the molecular interaction involved in the inhibition process of nicotinic acetylcholine receptor by anatoxin-a by using Glide 5.9. Our results clearly indicates that anatoxin-a bind to the A-chain of nAChR with hydrophobic interactions between anatoxin-a and Phe214, Tyr277 and Thr281 residues of protein with bond length 1.97, 1.96 and 2.04 A, respectively. The glide energy and docking score were found to be -18.242 and -4.567, respectively.   Key words: Anatoxin-a, Neurotoxin, Acetylcholine, Gaussian 09, molecular docking, glide.