title: First determination of the inhibitor complex structure of human hematopoietic prostaglandin D synthase.
abstract: Hematopoietic prostaglandin (PG) D synthase (H-PGDS) is responsible for the production of PGD(2) as an allergy or inflammation mediator in mast and Th2 cells. We determined the X-ray structure of human H-PGDS complexed with an inhibitor, 2-(2'-benzothiazolyl)-5-styryl-3-(4'-phthalhydrazidyl) tetrazolium chloride (BSPT) at 1.9 A resolution in the presence of Mg(2+). The styryl group of the inhibitor penetrated to the bottom of the active site cleft, and the tetrazole ring was stabilized by the stacking interaction with Trp104, inducing large movement around the alpha5-helix, which caused the space group of the complex crystal to change from P2(1) to P1 upon binding of BSPT. The phthalhydrazidyl group of BSPT exhibited steric hindrance due to the cofactor, glutathione (GSH), increasing the IC(50) value of BSPT for human H-PGDS from 36.2 micro M to 98.1 micro M upon binding of Mg(2+), because the K(m) value of GSH for human H-PGDS was decreased from 0.60 micro M in the presence of EDTA to 0.14 micro M in the presence of Mg(2+). We have to avoid steric hindrance of the GSH molecule that was stabilized by intracellular Mg(2+) in the mM range in the cytosol for further development of structure-based anti-allergic drugs.
authors.affiliation: Department of Materials Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Inoue
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Okano
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kado
authors.forename: Kousuke
authors.initials: K
authors.lastname: Aritake
authors.forename: Daisuke
authors.initials: D
authors.lastname: Irikura
authors.forename: Nobuko
authors.initials: N
authors.lastname: Uodome
authors.forename: Nobuo
authors.initials: N
authors.lastname: Okazaki
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kinugasa
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Shishitani
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Matsumura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kai
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Urade
mesh_terms: D052160:Benzothiazoles; D018360:Crystallography, X-Ray; D006413:Hematopoietic System / Q000201:enzymology*; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D054834:Lipocalins; D008958:Models, Molecular; D013778:Tetrazolium Salts / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D052160:Benzothiazoles; D054834:Lipocalins; D013778:Tetrazolium Salts; C024091:BSPT salt; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase