title: Inverting the regioselectivity of the berberine bridge enzyme by employing customized fluorine-containing substrates.
abstract: Fluorine is commonly applied in pharmaceuticals to block the degradation of bioactive compounds at a specific site of the molecule. Blocking of the reaction center of the enzyme-catalyzed ring closure of 1,2,3,4-tetrahydrobenzylisoquinolines by a fluoro moiety allowed redirecting the berberine bridge enzyme (BBE)-catalyzed transformation of these compounds to give the formation of an alternative regioisomeric product namely 11-hydroxy-functionalized tetrahydroprotoberberines instead of the commonly formed 9-hydroxy-functionalized products. Alternative strategies to change the regioselectivity of the enzyme, such as protein engineering, were not applicable in this special case due to missing substrate-enzyme interactions. Medium engineering, as another possible strategy, had clear influence on the regioselectivity of the reaction pathway, but did not lead to perfect selectivity. Thus, only substrate tuning by introducing a fluoro moiety at one potential reactive carbon center switched the reaction to the formation of exclusively one regioisomer with perfect enantioselectivity.
authors.affiliation: Department of Chemistry, Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Resch
authors.forename: Horst
authors.initials: H
authors.lastname: Lechner
authors.forename: Joerg H
authors.initials: JH
authors.lastname: Schrittwieser
authors.forename: Silvia
authors.initials: S
authors.lastname: Wallner
authors.forename: Karl
authors.initials: K
authors.lastname: Gruber
authors.forename: Peter
authors.initials: P
authors.lastname: Macheroux
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kroutil
mesh_terms: D005461:Fluorine / Q000737:chemistry*; D007546:Isoquinolines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010089:Oxidoreductases, N-Demethylating / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D007546:Isoquinolines; D005461:Fluorine; C071690:reticuline oxidase; D010089:Oxidoreductases, N-Demethylating