title: Cation-π Interactions Contribute to Substrate Recognition in γ-Butyrobetaine Hydroxylase Catalysis.
abstract: γ-Butyrobetaine hydroxylase (BBOX) is a non-heme Fe(II) - and 2-oxoglutarate-dependent oxygenase that catalyzes the stereoselective hydroxylation of an unactivated C-H bond of γ-butyrobetaine (γBB) in the final step of carnitine biosynthesis. BBOX contains an aromatic cage for the recognition of the positively charged trimethylammonium group of the γBB substrate. Enzyme binding and kinetic analyses on substrate analogues with P and As substituting for N in the trimethylammonium group show that the analogues are good BBOX substrates, which follow the efficiency trend N(+) >P(+) >As(+). The results reveal that an uncharged carbon analogue of γBB is not a BBOX substrate, thus highlighting the importance of the energetically favorable cation-π interactions in productive substrate recognition.
authors.affiliation: Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: Jos J A G
authors.initials: JJ
authors.lastname: Kamps
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Amjad
authors.initials: A
authors.lastname: Khan
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Hwanho
authors.initials: H
authors.lastname: Choi
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Lesniak
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Brem
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Rydzik
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: McDonough
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Schofield
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Timothy D W
authors.initials: TD
authors.lastname: Claridge
authors.affiliation: Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands. j.mecinovic@science.ru.nl.
authors.forename: Jasmin
authors.identifier: http://orcid.org/0000-0002-5559-3822
authors.initials: J
authors.lastname: Mecinović
mesh_terms: D001622:Betaine / Q000031:analogs & derivatives* / Q000737:chemistry; D002331:Carnitine / Q000737:chemistry*; D002384:Catalysis; D002412:Cations / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D011485:Protein Binding; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D050563:gamma-Butyrobetaine Dioxygenase / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002412:Cations; D000644:Quaternary Ammonium Compounds; D001622:Betaine; C002889:gamma-butyrobetaine; D050563:gamma-Butyrobetaine Dioxygenase; D002331:Carnitine
keywords: C−H oxidation; cation-pi interactions; enzyme catalysis; molecular recognition; oxygenases