caa a22 4500 606207910 CHVBK 20210128101019.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00425-015-2261-0 doi (NATIONALLICENCE)springer-10.1007/s00425-015-2261-0 Latent and active aurone synthase from petals of C. grandiflora [Elektronische Daten] a polyphenol oxidase with unique characteristics [Christian Molitor, Stephan Mauracher, Sanela Pargan, Rupert Mayer, Heidi Halbwirth, Annette Rompel] Main conclusion : Aurone synthase belongs to the novel group 2 polyphenol oxidases and the presented kinetic characterization suggests a differing aurone biosynthesis in Asteraceae species compared to snapdragon. Aurone synthases (AUS) are polyphenol oxidases (PPO) physiologically involved in the formation of yellow aurone pigments in petals of various Asteraceae species. They catalyze the oxidative conversion of chalcones into aurones. Latent (58.9kDa) and active (41.6kDa) aurone synthase from petals of C. grandiflora was purified by a quantitative removal of pigments using aqueous two-phase separation and several subsequent chromatographic steps. The purified enzymes were identified as cgAUS1 (A0A075DN54) and sequence analysis revealed that cgAUS1 is a member of a new group of plant PPOs. Mass determination experiments of intact cgAUS1 gave evidence that the C-terminal domain, usually shielding the active site of latent polyphenol oxidases, is linked to the main core by a disulfide bond. This is a novel and unique structural feature of plant PPOs. Proteolytic activation in vivo leads to active aurone synthase possessing a residual peptide of the C-terminal domain. Kinetic characterization of purified cgAUS1 strongly suggests a specific involvement in 4-deoxyaurone biosynthesis in Coreopsis grandiflora (Asteraceae) that differs in various aspects compared to the 4-hydroxyaurone formation in Antirrhinum majus (Plantaginaceae): cgAUS1 is predicted to be localized in the thylakoid lumen, it possesses exclusively diphenolase activity and the results suggest that aurone formation occurs at the level of chalcone aglycones. The latent enzyme exhibits allosteric activation which changes at a specific product concentration to a constant reaction rate. The presented novel structural and functional properties of aurone synthase provide further insights in the diversity and role of plant PPOs. The Author(s), 2015 Allosteric activation nationallicence Aurone synthase nationallicence 4-Deoxyaurone nationallicence Polyphenol oxidase nationallicence Proteolytic activation nationallicence Type-3 copper enzyme nationallicence AEX : Anion exchange nationallicence ATPS : Aqueous two-phase separation nationallicence cg AUS : Coreopsis grandiflora aurone synthase nationallicence CEX : Cation exchange nationallicence CV : Column volumes nationallicence DTT : dl-Dithiothreitol nationallicence MWCO : Molecular weight cut off nationallicence PPO(s) : Polyphenol oxidase(s) nationallicence vv CO : Vitis vinifera catechol oxidase nationallicence Molitor Christian Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut Mauracher Stephan Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut Pargan Sanela Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut Mayer Rupert Department of Analytical Chemistry, University of Vienna, Währinger Straße 38, 1090, Vienna, Austria aut Halbwirth Heidi Institute of Chemical Engineering, University of Technology Vienna, Getreidemarkt 9, 1060, Vienna, Austria aut Rompel Annette Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut Planta Springer Berlin Heidelberg 242/3(2015-09-01), 519-537 0032-0935 242:3<519 2015 242 425 https://doi.org/10.1007/s00425-015-2261-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00425-015-2261-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Molitor Christian Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut NATIONALLICENCE 700 1- Mauracher Stephan Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut NATIONALLICENCE 700 1- Pargan Sanela Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut NATIONALLICENCE 700 1- Mayer Rupert Department of Analytical Chemistry, University of Vienna, Währinger Straße 38, 1090, Vienna, Austria aut NATIONALLICENCE 700 1- Halbwirth Heidi Institute of Chemical Engineering, University of Technology Vienna, Getreidemarkt 9, 1060, Vienna, Austria aut NATIONALLICENCE 700 1- Rompel Annette Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, Althanstraße 14, 1090, Vienna, Austria aut NATIONALLICENCE 773 0- Planta Springer Berlin Heidelberg 242/3(2015-09-01), 519-537 0032-0935 242:3<519 2015 242 425