title: Regio- and Enantioselective Sequential Dehalogenation of rac-1,3-Dibromobutane by Haloalkane Dehalogenase LinB.
abstract: The hydrolytic dehalogenation of rac-1,3-dibromobutane catalyzed by the haloalkane dehalogenase LinB from Sphingobium japonicum UT26 proceeds in a sequential fashion: initial formation of intermediate haloalcohols followed by a second hydrolytic step to produce the final diol. Detailed investigation of the course of the reaction revealed favored nucleophilic displacement of the sec-halogen in the first hydrolytic event with pronounced R enantioselectivity. The second hydrolysis step proceeded with a regioselectivity switch at the primary position, with preference for the S enantiomer. Because of complex competition between all eight possible reactions, intermediate haloalcohols formed with moderate to good ee ((S)-4-bromobutan-2-ol: up to 87 %). Similarly, (S)-butane-1,3-diol was formed at a maximum ee of 35 % before full hydrolysis furnished the racemic diol product.
authors.affiliation: Department of Chemistry, University of Graz, Heinrichstrasse 28, 8010, Graz, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Gross
authors.affiliation: Department Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5A13, 625 00, Brno, Czech Republic.
authors.forename: Zbyněk
authors.initials: Z
authors.lastname: Prokop
authors.affiliation: Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, NL.
authors.forename: Dick
authors.initials: D
authors.lastname: Janssen
authors.affiliation: Department of Chemistry, University of Graz, Heinrichstrasse 28, 8010, Graz, Austria.
authors.forename: Kurt
authors.initials: K
authors.lastname: Faber
authors.affiliation: Department of Chemistry, University of Graz, Heinrichstrasse 28, 8010, Graz, Austria. melanie.hall@uni-graz.at.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Hall
mesh_terms: D002072:Butylene Glycols / Q000138:chemical synthesis; D054879:Halogenation; D006867:Hydrolases / Q000378:metabolism*; D006868:Hydrolysis; D042301:Sphingomonadaceae / Q000201:enzymology*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D002072:Butylene Glycols; D006867:Hydrolases; C046137:haloalkane dehalogenase
keywords: LinB; biocatalysis; enantioselectivity; haloalkane dehalogenase; hydrolysis; regioselectivity