Search

The peroxiredoxins (Prxs), potential drug targets, constitute an important class of antioxidant enzymes present in both pathogen and their host. The comparative binding potential of inhibitors to Prxs from pathogen and host could be an important step in drug development against pathogens. Huanglongbing (HLB) is a most devastating disease of citrus caused by Candidatus Liberibacter asiaticus (CLa). In this study, the binding of conoidin-A (conoidin) and celastrol inhibitor molecules to peroxiredoxin of bacterioferritin comigratory protein family from CLa (CLaBCP) and its host plant peroxiredoxin from Citrus sinensis (CsPrx) was assessed. The CLaBCP has a lower specific activity than CsPrx and is efficiently inhibited by conoidin and celastrol molecules. The biophysical studies showed conformational changes and significant thermal stability of CLaBCP in the presence of inhibitor molecules as compared to CsPrx. The surface plasmon resonance (SPR) studies revealed that the conoidin and celastrol inhibitor molecules have a strong binding affinity (K D ) with CLaBCP at 33.0 µM, and 18.5 µM as compared to CsPrx at 52.0 µM and 61.6 µM, respectively. The docked complexes of inhibitor molecules showed more structural stability of CLaBCP as compared to CsPrx during the run of molecular dynamics-based simulations for 100 ns. The present study suggests that the conoidin and celastrol molecules can be exploited as potential inhibitor molecules against the CLa to manage the HLB disease., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In present work, the recombinant cytoplasmic 2-Cys peroxiredoxin from Citrus sinensis (CsPrx) was purified and characterized. The peroxidase activity was examined with different substrates using DTT, a non-physiological electron donor. The conformational studies, in oxidized and reduced states, were performed using circular dichroism (CD) and fluorescence measurement. The CD analysis showed higher α-helical content for reduced state of the protein. The thermal stability studies of CsPrx by Differential Scanning Calorimetry (DSC) showed that oxidized state is more stable as compared to the reduced state of CsPrx. In vitro studies showed that the CsPrx provides a protective shield against ROS and free radicals that participate in the degradation of plasmid DNA. The pre-treatment of 10 μM CsPrx provide almost 100% protection against peroxide-mediated cell killing in the Vero cells. CsPrx showed significant cell proliferation and wound healing properties. The superior morphology of viable cells and wound closure was found at 20 μM CsPrx treated for 12 h. The results demonstrated that CsPrx is a multifaceted protein with a significant role in cell proliferation, wound healing and protection against hydrogen peroxide-induced cellular damage. This could be the first report of a plant peroxiredoxin being characterized for biomedical applications., (Copyright © 2022 Elsevier B.V. All rights reserved.)