title: Novel membrane-associated prostaglandin E synthase-2 from crustacean arthropods.
abstract: Prostaglandins (PG) have been shown to play important physiological roles in insects and marine invertebrates, yet the knowledge of their biosynthetic pathways is often lacking. Recently, we described cyclooxygenases in two amphipod crustaceans, Gammarus sp. and Caprella sp. In the present study, we report the cloning and characterization of prostaglandin E synthases (PGES) from the same organisms. The amphipod membrane-bound PGES-2-type enzymes share about 40% of the amino acid sequence identity with human mPGES-2, contain a conserved Cys110-x-x-Cys113 motif and have very low heme-binding affinity. The recombinant enzymes purified in the absence of dithiothreitol specifically catalyze the isomerization of PGH2 into PGE2. The PGES activity is increased in the presence of reduced glutathione and inhibited with a sulfhydryl group inhibitor. We assume that the amphipod mPGES-2, unlike in their mammalian counterparts, is responsible for PGE2 synthesis, not only in vitro but also in vivo.
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
authors.forename: Kristella
authors.initials: K
authors.lastname: Hansen
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
authors.forename: Külliki
authors.initials: K
authors.lastname: Varvas
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
authors.forename: Ivar
authors.initials: I
authors.lastname: Järving
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia. Electronic address: nigulas.samel@ttu.ee.
authors.forename: Nigulas
authors.initials: N
authors.lastname: Samel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003445:Crustacea / Q000378:metabolism*; D015232:Dinoprostone / Q000737:chemistry; D006418:Heme / Q000737:chemistry; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007536:Isomerism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D044262:Prostaglandin H2 / Q000737:chemistry; D000071876:Prostaglandin-E Synthases
chemical_list: D008565:Membrane Proteins; D044262:Prostaglandin H2; D006418:Heme; D019746:Intramolecular Oxidoreductases; C000605863:PTGES2 protein, human; D000071876:Prostaglandin-E Synthases; D015232:Dinoprostone
keywords: Arthropod; Crustacean; Cyclooxygenase; Membrane associated prostaglandin E synthase-2; PGES gene