title: Probing the interaction between prostacyclin synthase and prostaglandin H2 analogues or inhibitors via a combination of resonance Raman spectroscopy and molecular dynamics simulation approaches.
abstract: In an aim to probe the structure-function relationship of prostacyclin synthase (PGIS), resonance Raman (RR) spectroscopy and molecular dynamic (MD) simulation approaches have been exploited to characterize the heme conformation and heme-protein matrix interactions for human PGIS (hPGIS) and zebrafish PGIS (zPGIS) in the presence and absence of ligands. The high-frequency RR (1300-1700 cm(-1)) indicates that the heme group is in the ferric, six-coordinate, low-spin state for both resting and ligand-bound hPGIS/zPGIS. The low-frequency RR (300-500 cm(-1)) and MD simulation reveal a salient difference in propionate-protein matrix interactions between hPGIS and zPGIS, as evident by a predominant propionate bending vibration at 386 cm(-1) in resting hPGIS, but two vibrations near 370 and 387 cm(-1) in resting zPGIS. Upon binding of a substrate analogue (U46619, U51605, or U44069), both hPGIS and zPGIS induce a distinctive perturbation of the propionate-protein matrix interactions, resulting in similar Raman shifts to ~381 cm(-1). On the contrary, the bending vibration remains unchanged upon binding of inhibitor/ligand (minoxidil, clotrimazole, or miconazole), indicating that these inhibitors/ligands do not interfere with the propionate-protein matrix interactions. These results, together with subtle changes in vinyl bending modes, demonstrate drastically different RR shifts with heme conformational changes in both hPGIS and zPGIS upon different ligand bindings, suggesting that PGIS exhibits a ligand-specific heme conformational change to accommodate the substrate binding. This substrate-induced modulation of the heme conformation may confer high product fidelity upon PGIS catalysis.
authors: Graduate Institute of Applied Science and Engineering, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, Republic of China.
authors: Wei-Chih
authors: WC
authors: Chao
authors: Jyh-Feng
authors: JF
authors: Lu
authors: Jinn-Shyan
authors: JS
authors: Wang
authors: Hsiao-Ching
authors: HC
authors: Yang
authors: Hsiao-Hui
authors: HH
authors: Chen
authors: Yi-Kang
authors: YK
authors: Lan
authors: Ya-Chien
authors: YC
authors: Yu
authors: Pi-Tai
authors: PT
authors: Chou
authors: Lee-Ho
authors: LH
authors: Wang
mesh_terms: D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D044262:Prostaglandin H2 / Q000737:chemistry* / Q000378:metabolism; D011465:Prostaglandins, Synthetic / Q000737:chemistry* / Q000378:metabolism; D013059:Spectrum Analysis, Raman
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D008024:Ligands; D011465:Prostaglandins, Synthetic; D044262:Prostaglandin H2; D003577:Cytochrome P-450 Enzyme System; D019746:Intramolecular Oxidoreductases; C022461:prostacyclin synthetase