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From Proteopedia
Human hematopoietic prostaglandin D synthase inhibitor complex structures
Structural highlights
Function[HPGDS_HUMAN] Bifunctional enzyme which catalyzes both the conversion of PGH2 to PGD2, a prostaglandin involved in smooth muscle contraction/relaxation and a potent inhibitor of platelet aggregation, and the conjugation of glutathione with a wide range of aryl halides and organic isothiocyanates. Also exhibits low glutathione-peroxidase activity towards cumene hydroperoxide.[1] [2] [3] [4] [5] [6] [7] [8] Publication Abstract from PubMedIn mast and Th2 cells, hematopoietic prostaglandin (PG) D synthase (H-PGDS) catalyses the isomerization of PGH(2) in the presence of glutathione (GSH) to produce the allergic and inflammatory mediator PGD(2). We determined the X-ray structures of human H-PGDS inhibitor complexes with 1-amino-4-{4-[4-chloro-6-(2-sulpho-phenylamino)-[1,3,5]triazin-2-ylmethyl]-3-sulp ho-phenylamino}-9,10-dioxo-9,10-dihydro-anthracene-2-sulphonic acid (Cibacron Blue) and 1-amino-4-(4-aminosulphonyl) phenyl-anthraquinone-2-sulphonic acid (APAS) at 2.0 A resolution. When complexed with H-PGDS, Cibacron Blue had an IC(50) value of 40 nM and APAS 2.1 muM. The Cibacron Blue molecule was stabilized by four hydrogen bonds and pi-pi stacking between the anthraquinone ring and Trp104, the ceiling of the active site H-PGDS pocket. Among the four hydrogen bonds, the Cibacron Blue terminal sulphonic group directly interacted with conserved residues Lys112 and Lys198, which recognize the PGH(2) substrate alpha-chain. In contrast, the APAS anthraquinone ring was inverted to interact with Trp104, while its benzenesulphonic group penetrated the GSH-bound region at the bottom of the active site. Due to the lack of extended aromatic rings, APAS could not directly hydrogen bond with the two conserved lysine residues, thus decreasing the total number of hydrogen bond from four to one. These factors may contribute to the 50-fold difference in the IC(50) values obtained for the two inhibitors. Human hematopoietic prostaglandin D synthase inhibitor complex structures.,Kado Y, Aritake K, Uodome N, Okano Y, Okazaki N, Matsumura H, Urade Y, Inoue T J Biochem. 2012 Apr;151(4):447-55. Epub 2012 Mar 13. PMID:22418579[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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