Deciphering the binding mode of Zolpidem to GABAA α1 receptor – insights from molecular dynamics simulation
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- Vijayan, R.S.K., Bhattacharyya, D. & Ghoshal, N. J Mol Model (2012) 18: 1345. doi:10.1007/s00894-011-1142-0
To investigate the binding mode of Zolpidem to GABAA and to delineate the conformational changes induced upon agonist binding, we carried out atomistic molecular dynamics simulation using the ligand binding domain of GABAA α1 receptor. Comparative molecular dynamics simulation of the apo and the holo form of GABAA receptor revealed that γ2/α1 interface housing the benzodiazepine binding site undergoes distinct conformational changes upon Zolpidem binding. We notice that C loop of the α1 subunit experiences an inward motion toward the vestibule and the F loop of γ2 sways away from the vestibule, an observation that rationalizes Zolpidem as an alpha1 selective agonist. Energy decomposition analysis carried out was able to highlight the important residues implicated in Zolpidem binding, which were largely in congruence with the experimental data. The simulation study disclosed herein provides a meaningful insight into Zolpidem-GABAAR interactions and helps to arrive at a binding mode hypothesis with implications for drug design.