title: Prediction of substrate specificity and preliminary kinetic characterization of the hypothetical protein PVX_123945 from Plasmodium vivax.
abstract: Members of the haloacid dehalogenase (HAD) superfamily are emerging as an important group of enzymes by virtue of their role in diverse chemical reactions. In different Plasmodium species their number varies from 16 to 21. One of the HAD superfamily members, PVX_123945, a hypothetical protein from Plasmodium vivax, was selected for examining its substrate specificity. Based on distant homology searches and structure comparisons, it was predicted to be a phosphatase. Thirty-eight metabolites were screened to identify potential substrates. Further, to validate the prediction, biochemical and kinetic studies were carried out that showed that the protein was a monomer with high catalytic efficiency for β-glycerophosphate followed by pyridoxal 5'-phosphate. The enzyme also exhibited moderate catalytic efficiencies for α-glycerophosphate, xanthosine 5'-monophosphate and adenosine 5'-monophosphate. It also hydrolyzed the artificial substrate p-nitrophenyl phosphate (pNPP). Mg(2+) was the most preferred divalent cation and phosphate inhibited the enzyme activity. The study is the first attempt at understanding the substrate specificity of a hypothetical protein belonging to HAD superfamily from the malarial parasite P. vivax.
authors: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, Karnataka, India.
authors: Bharath
authors: B
authors: Srinivasan
authors: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, Karnataka, India.
authors: Lakshmeesha
authors: L
authors: Kempaiah Nagappa
authors: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, Karnataka, India.
authors: Arpit
authors: A
authors: Shukla
authors: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, Karnataka, India. Electronic address: hb@jncasr.ac.in.
authors: Hemalatha
authors: H
authors: Balaram
mesh_terms: D000249:Adenosine Monophosphate / Q000378:metabolism; D019295:Computational Biology; D005994:Glycerophosphates / Q000378:metabolism*; D006867:Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D015394:Molecular Structure; D008970:Molecular Weight; D009596:Nitrophenols / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D010710:Phosphates / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D010966:Plasmodium vivax / Q000201:enzymology*; D017510:Protein Folding; D011732:Pyridoxal Phosphate / Q000378:metabolism*; D012265:Ribonucleotides / Q000378:metabolism; D013379:Substrate Specificity; D019820:Xanthine
chemical_list: D005994:Glycerophosphates; D009596:Nitrophenols; D009943:Organophosphorus Compounds; D010710:Phosphates; D012265:Ribonucleotides; D019820:Xanthine; C008644:nitrophenylphosphate; D000249:Adenosine Monophosphate; C011141:xanthosine monophosphate; D011732:Pyridoxal Phosphate; C029620:alpha-glycerophosphoric acid; D006867:Hydrolases; C020674:glycerol-2-phosphatase; D010744:Phosphoric Monoester Hydrolases; C034507:2-haloacid dehalogenase; D008274:Magnesium; C031463:beta-glycerophosphoric acid
keywords: Docking; Hypothetical protein; In silico function annotation; Multiple-structure alignment; Phosphatase; Substrate screen; Sugar hydrolase