Mechanistic understanding of PHD2 enzyme upon ligand interactions using SAXS and SANS

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Date
2017-07-12
Journal Title
Journal ISSN
Volume Title
Publisher
International Conference on Neutron Scattering
Abstract
Prolyl hydroxylase domain proteins (PHDs) play an important role in the regulation of cellular homeostasis in response to changes in cellular oxygen level.1 In the presence of oxygen, PHDs catalyse the oxygen-dependent hydroxylation of hypoxia inducible factor (HIF), which lead to its degradation. However, in the absence of oxygen, HIF cannot be hydroxylated and can therefore trigger downstream hypoxic responses including the formation of new blood vessels and red bloodcells. PHDs catalyse the hydroxylation of HIF at two different proline residues.2–3 We are interested in understanding the structural basis in the substrate selectivity of PHDs. Using small angle X-ray scattering (SAXS), we examined the conformational changes of PHD2 particularly ?2 ?3 loop in the presence of CODD and NODD substrates where we see change in overall size and shape of PHD2. We obtained PHD2-NODDsolution structure as a confirmation to crystallographic structure3. We would further confirm these conformational changes upon ligand interactions using Small angle neutron scattering. It would help us in understand ?2 ?3 loopand ?4 regions of PHD2 which is crucial in binding of CODD and NODD substrates. The contribution of ?2 ?3 loop and ?4 regions of PHD2 in protecting the active site is known from the NMR data2–3. Both SAXS and SANS would be complementary to NMR data in solution which would further help us in design PHD2 inhibitors for hypoxia related diseases like ischemic heart disease and anaemia.
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Keywords
Anoxia, Cardiovascular diseases, X-ray diffraction, Small angle scattering, Proteins, Homeostasis, Oxygen
Citation
Vadakkedath, P. G., Ryan, T. M., Leung, I. K. H., & McGillivray, D. J. (2017). Mechanistic understanding of PHD2 enzyme upon ligand interactions using SAXS and SANS. Paper presented at ICNS 2017 (International Conference on Neutron Scattering), Daejeon, South Korea, 9 to 13 July 2017. Retrieved from: http://www.icns2017.org/program.php