Structural and activity characterization of human PHPT1 after oxidative modification
| Autor: | Sameer Varma, Priyanka Dutta, Shikha Mahajan, Daniel R Martin, Stanley M. Stevens |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Potassium ion transport Phosphatase Oxidative phosphorylation Molecular Dynamics Simulation Protein oxidation Article 03 medical and health sciences chemistry.chemical_compound Methionine Tandem Mass Spectrometry Catalytic Domain Humans Protein phosphorylation Histidine Phosphorylation Hydrogen peroxide chemistry.chemical_classification Reactive oxygen species Multidisciplinary 030102 biochemistry & molecular biology Chemistry Substrate (chemistry) Hydrogen Peroxide Oxidants Phosphoric Monoester Hydrolases Recombinant Proteins 030104 developmental biology Biochemistry Oxidation-Reduction Protein Processing Post-Translational |
| Zdroj: | Scientific Reports |
| ISSN: | 2045-2322 |
| Popis: | Phosphohistidine phosphatase 1 (PHPT1), the only known phosphohistidine phosphatase in mammals, regulates phosphohistidine levels of several proteins including those involved in signaling, lipid metabolism, and potassium ion transport. While the high-resolution structure of human PHPT1 (hPHPT1) is available and residues important for substrate binding and catalytic activity have been reported, little is known about post-translational modifications that modulate hPHPT1 activity. Here we characterize the structural and functional impact of hPHPT1 oxidation upon exposure to a reactive oxygen species, hydrogen peroxide (H2O2). Specifically, liquid chromatography-tandem mass spectrometry was used to quantify site-specific oxidation of redox-sensitive residues of hPHPT1. Results from this study revealed that H2O2 exposure induces selective oxidation of hPHPT1 at Met95, a residue within the substrate binding region. Explicit solvent molecular dynamics simulations, however, predict only a minor effect of Met95 oxidation in the structure and dynamics of the apo-state of the hPHPT1 catalytic site, suggesting that if Met95 oxidation alters hPHPT1 activity, then it will do so by altering the stability of an intermediate state. Employing a novel mass spectrometry-based assay, we determined that H2O2–induced oxidation does not impact hPHPT1 function negatively; a result contrary to the common conception that protein oxidation is typically a loss-of-function modification. |
| Databáze: | OpenAIRE |
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