Probing the Interaction between Prostacyclin Synthase and Prostaglandin H2 Analogues or Inhibitors via a Combination of Resonance Raman Spectroscopy and Molecular Dynamics Simulation Approa

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• 作者：Wei-Chih Chao ; Jyh-Feng Lu ; Jinn-Shyan Wang ; Hsiao-Ching Yang ; Hsiao-Hui Chen ; Yi-Kang Lan ; Ya-Chien Yu ; Pi-Tai Chou ; Lee-Ho Wang
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：November 23, 2011
• 年：2011
• 卷：133
• 期：46
• 页码：18870-18879
• 全文大小：1024K
• 年卷期：v.133,no.46(November 23, 2011)
• ISSN：1520-5126

文摘

In an aim to probe the structure鈥揻unction 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鈥損rotein matrix interactions for human PGIS (hPGIS) and zebrafish PGIS (zPGIS) in the presence and absence of ligands. The high-frequency RR (1300鈥?700 cm^鈥?) 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鈥?00 cm^鈥?) and MD simulation reveal a salient difference in propionate鈥損rotein matrix interactions between hPGIS and zPGIS, as evident by a predominant propionate bending vibration at 386 cm^鈥? in resting hPGIS, but two vibrations near 370 and 387 cm^鈥? in resting zPGIS. Upon binding of a substrate analogue (U46619, U51605, or U44069), both hPGIS and zPGIS induce a distinctive perturbation of the propionate鈥損rotein matrix interactions, resulting in similar Raman shifts to 381 cm^鈥?. 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鈥損rotein 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.