title: Reconstitution of Vanadium Haloperoxidase's Catalytic Activity by Boric Acid-Towards a Potential Biocatalytic Role of Boron.
abstract: Boron's unusual properties inspired major advances in chemistry. In nature, the existence and importance of boron has been fairly explored (e.g. bacterial signaling, plant development) but its role as biological catalyst was never reported. Here, we show that boric acid [B(OH)3] can restore chloroperoxidase activity of Curvularia inaequalis recombinant apo-haloperoxidase's (HPO) in the presence of hydrogen peroxide and chloride ions. Molecular modeling and semi-empirical PM7 calculations support a thermodynamically highly favored (bio)catalytic mechanism similarly to vanadium haloperoxidases (V-HPO) in which [B(OH)3] is assumedly located in apo-HPO's active site and a monoperoxyborate [B(OH)3(OOH)-] intermediate is formed and stabilized by interaction with specific active site amino acids leading ultimately to the formation of HOCl. Thus, B(OH)3-HPO provides the first evidence towards the future exploitation of boron's role in biological systems.
authors.affiliation: Kimmel Center for Archaeological Science, Weizmann Institute of Science, Rehovot, 76100, Israel.|Institut für Chemie-Anorganische Chemie, Naturwissenschaftliche Fakultät II-Chemie, Physik und Mathematik, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Straße 2, 06120, Halle, Germany.
authors.forename: Filipe
authors.identifier: http://orcid.org/0000-0002-4166-6947
authors.initials: F
authors.lastname: Natalio
authors.affiliation: Institut für Chemie-Anorganische Chemie, Naturwissenschaftliche Fakultät II-Chemie, Physik und Mathematik, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Straße 2, 06120, Halle, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Wiese
authors.affiliation: Leibniz Institute of Plant Biochemistry, Department of Bioorganic Chemistry, Weinberg 3, Halle, Germany.
authors.forename: Wolfgang
authors.identifier: http://orcid.org/0000-0002-0825-1491
authors.initials: W
authors.lastname: Brandt
authors.affiliation: Leibniz Institute of Plant Biochemistry, Department of Bioorganic Chemistry, Weinberg 3, Halle, Germany.
authors.forename: Ludger
authors.identifier: http://orcid.org/0000-0003-2060-8235
authors.initials: L
authors.lastname: Wessjohann
keywords: active site redesign; biocatalysis; bioinorganic chemistry; boric acid; semi-empiric calculations