Comparative Study on the Binding Affinity of Methimazole and Propylthiouracil to Thyroid Peroxidase as an Anti-Thyroid Drug: An Insilico Approach
Sushmita Pradhan, Himakshi Sarma, Barsha Bharadwaz and Venkata Satish Kumar Mattaparthi*
Molecular Modelling and Simulation Lab, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur-784 028, Assam, India
- *Corresponding Author:
- Venkata Satish Kumar Mattaparthi
Molecular Modelling and Simulation Lab
Department of Molecular Biology and Biotechnology
Tezpur University, Tezpur-784 028, Assam, India
Tel: +91 08811806866
E-mail: [email protected]
Received date: June 1, 2017; Accepted date: June 21, 2017; Published date: June 26, 2017
Citation: Pradhan S, Sarma H, Bharadwaz B, Mattaparthi VSK (2017) Comparative Study on the Binding Affinity of Methimazole and Propylthiouracil to Thyroid Peroxidase as an Anti-Thyroid Drug: An In-silico Approach. J Mol Imag Dynamic 7:131. doi: 10.4172/2155-9937.1000131
Copyright: © Pradhan S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use,distribution, and reproduction in any medium, provided the original author and source are credited.
Graves’ disease (GD), an autoimmune disorder, scars majority of women worldwide, causing hyperthyroidism, Graves’s ophthalmopathy and goitre. Thyroid Peroxidase (TPO) is an active target of anti-thyroid drugs, Methimazole and Propylthiouracil, which inhibit the enzyme function of catalysing the thyroid hormones synthesis. Most of the protein-drug interaction studies so far have been focussed mainly at in vivo level, or by using Myeloperoxidase and Lactose peroxidases as TPO surrogates for the same. This makes the molecular interaction of TPO with the drugs crucial to understand. In this study, we used the molecular dynamics (MD) to study the molecular interaction differences between TPO201-500 and both drugs. The binding free energy calculation done using Molecular Mechanics Poisson–Boltzmann (MM-PBSA) and generalized Born and surface area continuum solvation (GBSA) results indicated that both drugs bind strongly to TPO201-500, with Propylthiouracil having slightly higher binding energy than Methimazole. We found that both drugs interacted with the residues- Asp238, His239, Phe243, Thr487 and His494 through hydrophobic interactions and formed stable hydrogen bonds with residue Arg491 of TPO201-500. Since both drugs engage residues- Asp238, His239 and His494 which falls within the proximal heme binding site and catalytic site of TPO201-500, we can conclude that these drugs may be conducive in inhibiting the enzymatic activity of TPO201-500.