title: New insights into the catalytic mechanism of Bombyx mori prostaglandin E synthase gained from structure-function analysis.
abstract: Prostaglandin E synthase (PGES) catalyzes the isomerization of PGH2 to PGE2. We previously reported the identification and structural characterization of Bombyx mori PGES (bmPGES), which belongs to Sigma-class glutathione transferase. Here, we extend these studies by determining the structure of bmPGES in complex with glutathione sulfonic acid (GTS) at a resolution of 1.37 Å using X-ray crystallography. GTS localized to the glutathione-binding site. We found that electron-sharing network of bmPGES includes Asn95, Asp96, and Arg98. Site-directed mutagenesis of these residues to create mutant forms of bmPGES mutants indicate that they contribute to catalytic activity. These results are, to our knowledge, the first to reveal the presence of an electron-sharing network in bmPGES.
authors.affiliation: Faculty of Agriculture, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. Electronic address: yamamok@agr.kyushu-u.ac.jp.
authors.forename: Kohji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Mamoru
authors.initials: M
authors.lastname: Suzuki
authors.forename: Akifumi
authors.initials: A
authors.lastname: Higashiura
authors.forename: Kosuke
authors.initials: K
authors.lastname: Aritake
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Urade
authors.forename: Nobuko
authors.initials: N
authors.lastname: Uodome
authors.forename: Tofazzal
authors.initials: T
authors.lastname: Hossain
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D001120:Arginine / Q000737:chemistry / Q000235:genetics; D001665:Binding Sites; D012831:Bombyx / Q000201:enzymology*; D002384:Catalysis; D018360:Crystallography, X-Ray; D004583:Electrons; D005978:Glutathione / Q000031:analogs & derivatives* / Q000737:chemistry; D019746:Intramolecular Oxidoreductases / Q000737:chemistry* / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D000071876:Prostaglandin-E Synthases; D011487:Protein Conformation
chemical_list: C040136:glutathione sulfonate; D001120:Arginine; D019746:Intramolecular Oxidoreductases; D000071876:Prostaglandin-E Synthases; D005978:Glutathione
keywords: Crystal structure; GSH; GST; GSTS; GTS; Glutathione; Lepidoptera; PG; PGDS; PGES; Prostaglandin; Prostaglandin synthase; SDS–PAGE; Sigma-class GST; glutathione; glutathione sulfonic acid; glutathione transferase; prostaglandin; prostaglandin D synthase; prostaglandin E synthase; sodium dodecyl sulfate polyacrylamide gel electrophoresis