Withdrawn.

Abstract

Mycobacterial inorganic pyrophosphatase (Mt-PPa) play essential role in bacterial in vitro and in vivo survival. This family of proteins reacts on inorganic pyrophosphate to release inorganic phosphate and protect bacteria from pyrophosphate toxicity. Rv3628 (Mt-PPa) encodes inorganic pyrophosphatase protein which is a type I pyrophosphatase with metal ion dependent activity. Apart from the inorganic pyrophosphatase activity, Rv3628 also showed binding with nucleotide tri phosphate (GTP/ATP). The binding of GTP and Rv3628 was analyzed by isothermal calorimetry. However, the GTP binding activity was mild but important to consider, as GTP is the secondary messenger and involved in number of mycobacterial cellular metabolic pathways therefore this interaction might be an important part of signaling cascades. This article thus represents a trilateral approach that considers computational and mutational analysis which was further complemented by virtual screening of natural compounds to find potential drug candidates. Computational analysis showed that Mt-PPa showed extensive interaction with GTP and ATP family genes. Epitope prediction showed the occurrence of amino acid regions in PPa that can act as immunological epitopes. PPa is sensitive to phosphorylation by several kinases that phosphorylate PPa at different Ser/Thr/Tyr sites. Mutational analysis showed W102G, V150G, F44G, I119G, L93F, F3G, F122G, I108G, L32G, M82G, Y17G, L59G, V5G, V26G, I7G, W140D, W140G, W140A, F80G, W140S, L49G, L56G, I9G, V60G, V19G, V92G, L28G, L61G, Y126E and F123G were the top 30 mutational hits and Y126G, Y42G, R30G, E8G, K16G are top mutational hits in active site of Mt-PPa. Mt-PPa activity is temperature and pH sensitive as the mutation in the His 21 and His 86 residues shift the optimal pH. Virtual screening of 700 compounds from herbal ingredient targets (HITs) subset of zinc database showed ZINC000003979028, ZINC000003870413, ZINC000003870412, ZINC000150338758, ZINC0000070450948, ZINC000150338754, ZINC000095098891, ZINC000000119985 and ZINC000005085286 as the top target hits and Mac0182344 and NAV_2729 as the top GTPase inhibitor that would target and hinders Mt-PPa activity. This article is protected by copyright. All rights reserved.