title: Microsomal prostaglandin E synthase-1 exhibits one-third-of-the-sites reactivity.
abstract: mPGES-1 (microsomal prostaglandin E synthase-1) is a newly recognized target for the treatment of inflammatory diseases. As the terminal enzyme of the prostaglandin production pathway, mPGES-1 inhibition may have a low risk of side effects. Inhibitors of mPGES-1 have attracted considerable attention as next-generation anti-inflammatory drugs. However, as mPGES-1 is a membrane protein, its enzymatic mechanism remains to be disclosed fully. We used MD (molecular dynamics) simulations, mutation analysis, hybrid experiments and co-IP (co-immunoprecipitation) to investigate the conformation transitions of mPGES-1 during catalysis. mPGES-1 forms a homotrimer with three substrate-binding sites (pockets). In the MD simulation, only one substrate molecule could bind to one of the pockets and form the active complex, suggesting that the mPGES-1 trimer has only one pocket active at any given time. This one-third-of-the-sites reactivity enzyme mechanism was verified further by hybridization experiments and MD simulations. The results of the present study revealed for the first time a novel one-third-of-the-sites reactivity enzyme mechanism for mPGES-1, and the unique substrate-binding pocket in our model constituted an active conformation that was suitable for further enzymatic mechanism study and structural-based drug design against mPGES-1.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Shan
authors.initials: S
authors.lastname: He
authors.forename: Yiran
authors.initials: Y
authors.lastname: Wu
authors.forename: Daqi
authors.initials: D
authors.lastname: Yu
authors.forename: Luhua
authors.initials: L
authors.lastname: Lai
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D003587:Cytomegalovirus / Q000201:enzymology / Q000235:genetics; D006801:Humans; D047468:Immunoprecipitation; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008861:Microsomes / Q000201:enzymology; D056004:Molecular Dynamics Simulation; D000071876:Prostaglandin-E Synthases; D011487:Protein Conformation; D055503:Protein Multimerization
chemical_list: D019746:Intramolecular Oxidoreductases; C000605862:PTGES protein, human; D000071876:Prostaglandin-E Synthases