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Title: Biochemical and biophysical insights into the metal binding spectrum and bioactivity of arginase of: Entamoeba histolytica
Authors: Malik A.
Singh H.
Pareek A.
Tomar, Shailly
Published in: Metallomics
Abstract: The human protozoan pathogens possess the essential metalloenzyme arginase (Arg) which catalyses the catabolism of l-arginine to l-ornithine and urea. This being the first committed step in polyamine biosynthesis is a potential drug target for protozoan diseases. In pathogenic organisms, arginase plays a crucial role in depleting host l-arginine, a substrate for nitric oxide synthase (NOS) that participates in protective immunity, thereby evading host immune response. In this study, the metal binding spectrum of EhArg has been determined. This study focuses on the biochemical and biophysical characterization of arginase from Entamoeba histolytica (EhArg), majorly characterizing the bivalent metal selectivity and metal binding kinetics of purified EhArg using Surface Plasmon Resonance and inductively coupled plasma mass spectroscopy. Investigation of the active site chemistry and total metal content using molecular docking and ICP-MS unraveled the fact that two Mn2+ ions are required for the enzyme to be fully functional. However, chelating loosely bound Mn2+ and replacing it with a variety of bivalent metal ions including Mg2+, Zn2+, Ni2+, Hg2+, Cu2+, Co2+, Ca2+ and Cd2+ retains its enzymatic activity. Further, the role of nine bivalent ions in the activation of EhArg was studied thermodynamically and biochemically. Phylogenetic and sequence analysis and oligomerization studies of EhArg show that unlike other eukaryotic arginases, EhArg exists in monomeric and dimeric form in solution and shows the highest similarity with bacterial arginase. This study unveiled interesting facts about EhArg that the enzyme has evolved to utilize available metal ion cofactors and survive the inhospitable environment within the host. © The Royal Society of Chemistry.
Citation: Metallomics(2018), 10(4): 623-638
Issue Date: 2018
Publisher: Royal Society of Chemistry
ISSN: 17565901
Author Scopus IDs: 57191902133
Author Affiliations: Malik, A., Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
Singh, H., Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
Pareek, A., Departm
Funding Details: The authors thank Serge Ankri (Department of Molecular Microbiology, The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel) for his kind gift of plasmid PGEX-4T-1 having EhArg gene. The authors thank Analytical Se
Corresponding Author: Tomar, S.; Department of Biotechnology, Indian Institute of Technology RoorkeeIndia; email:
Appears in Collections:Journal Publications [BT]

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