title: Structural Basis for Phospholyase Activity of a Class III Transaminase Homologue.
abstract: Pyridoxal-phosphate (PLP)-dependent enzymes catalyse a remarkable diversity of chemical reactions in nature. A1RDF1 from Arthrobacter aurescens TC1 is a fold type I, PLP-dependent enzyme in the class III transaminase (TA) subgroup. Despite sharing 28 % sequence identity with its closest structural homologues, including β-alanine:pyruvate and γ-aminobutyrate:α-ketoglutarate TAs, A1RDF1 displayed no TA activity. Activity screening revealed that the enzyme possesses phospholyase (E.C. 4.2.3.2) activity towards O-phosphoethanolamine (PEtN), an activity described previously for vertebrate enzymes such as human AGXT2L1, enzymes for which no structure has yet been reported. In order to shed light on the distinctive features of PLP-dependent phospholyases, structures of A1RDF1 in complex with PLP (internal aldimine) and PLP⋅PEtN (external aldimine) were determined, revealing the basis of substrate binding and the structural factors that distinguish the enzyme from class III homologues that display TA activity.
authors.affiliation: York Structural Biology Laboratory, University of York, Heslington, York, YO10 5DD, UK.
authors.forename: Anibal
authors.initials: A
authors.lastname: Cuetos
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, 751 24, Uppsala, Sweden.
authors.forename: Fabian
authors.initials: F
authors.lastname: Steffen-Munsberg
authors.affiliation: York Structural Biology Laboratory, University of York, Heslington, York, YO10 5DD, UK.
authors.forename: Juan
authors.initials: J
authors.lastname: Mangas Sanchez
authors.affiliation: York Structural Biology Laboratory, University of York, Heslington, York, YO10 5DD, UK.
authors.forename: Amina
authors.initials: A
authors.lastname: Frese
authors.affiliation: Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany.
authors.forename: Uwe T
authors.initials: UT
authors.lastname: Bornscheuer
authors.affiliation: Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Höhne
authors.affiliation: York Structural Biology Laboratory, University of York, Heslington, York, YO10 5DD, UK.
authors.forename: Gideon
authors.initials: G
authors.lastname: Grogan
mesh_terms: D001173:Arthrobacter / Q000201:enzymology; D001665:Binding Sites; D055162:Biocatalysis; D020134:Catalytic Domain; D006801:Humans; D056004:Molecular Dynamics Simulation; D011732:Pyridoxal Phosphate / Q000737:chemistry / Q000378:metabolism; D000637:Transaminases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011732:Pyridoxal Phosphate; D000637:Transaminases; C019635:Alanine-glyoxylate transaminase
keywords: enzyme catalysis; lyases; phospholyases; pyridoxal phosphate; racemases; transaminases