title: Molecular cloning, structure, and reactivity of the second bromoperoxidase from Ascophyllum nodosum.
abstract: The sequence of bromoperoxidase II from the brown alga Ascophyllum nodosum was determined from a full length cloned cDNA, obtained from a tandem mass spectrometry RT-PCR-approach. The clone encodes a protein composed of 641 amino-acids, which provides a mature 67.4 kDa-bromoperoxidase II-protein (620 amino-acids). Based on 43% sequence homology with the previously characterized bromoperoxidase I from A. nodosum, a tertiary structure was modeled for the bromoperoxidase II. The structural model was refined on the basis of results from gel filtration and vanadate-binding studies, showing that the bromoperoxidase II is a hexameric metalloprotein, which binds 0.5 equivalents of vanadate as cofactor per 67.4 kDa-subunit, for catalyzing oxidation of bromide by hydrogen peroxide in a bi-bi-ping-pong mechanism (k(cat) = 153 s(-1), 22 °C, pH 5.9). Bromide thereby is converted into a bromoelectrophile of reactivity similar to molecular bromine, based on competition kinetic data on phenol bromination and correlation analysis. Reactivity provided by the bromoperoxidase II mimics biosynthesis of methyl 4-bromopyrrole-2-carboxylate, a natural product isolated from the marine sponge Axinella tenuidigitata.
authors.affiliation: Fachbereich Chemie, Organische Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse, D-67663 Kaiserslautern, Germany.
authors.forename: Diana
authors.initials: D
authors.lastname: Wischang
authors.forename: Madlen
authors.initials: M
authors.lastname: Radlow
authors.forename: Heiko
authors.initials: H
authors.lastname: Schulz
authors.forename: Hans
authors.initials: H
authors.lastname: Vilter
authors.forename: Lutz
authors.initials: L
authors.lastname: Viehweger
authors.forename: Matthias O
authors.initials: MO
authors.lastname: Altmeyer
authors.forename: Carsten
authors.initials: C
authors.lastname: Kegler
authors.forename: Jennifer
authors.initials: J
authors.lastname: Herrmann
authors.forename: Rolf
authors.initials: R
authors.lastname: Müller
authors.forename: Fanny
authors.initials: F
authors.lastname: Gaillard
authors.forename: Ludovic
authors.initials: L
authors.lastname: Delage
authors.forename: Catherine
authors.initials: C
authors.lastname: Leblanc
authors.forename: Jens
authors.initials: J
authors.lastname: Hartung
mesh_terms: D000595:Amino Acid Sequence; D044646:Ascophyllum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D001965:Bromides / Q000378:metabolism*; D003001:Cloning, Molecular; D054879:Halogenation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D016415:Sequence Alignment; D014638:Vanadates / Q000378:metabolism
chemical_list: D001965:Bromides; D014638:Vanadates; D010544:Peroxidases; C026195:bromide peroxidase