Hydroxymethylated Phyllobilins: A Puzzling New Feature of the Dioxobilin Branch of Chlorophyll Breakdown |
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| Authors: | Iris Süssenbacher Dr. Bastien Christ Prof. Dr. Stefan Hörtensteiner Prof. Dr. Bernhard Kräutler |
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| Affiliation: | 1. Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria);2. Institute of Plant Biology, University of Zürich, Zollikerstrasse 107, 8008 Zürich (Switzerland) |
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| Abstract: | Colorless nonfluorescent chlorophyll (Chl) catabolites (NCCs) are formyloxobilin‐type phyllobilins, which are considered the typical products of Chl breakdown in senescent leaves. However, in degreened leaves of some plants, dioxobilin‐type Chl catabolites (DCCs) predominate, which lack the formyl group of the NCCs, and which arise from Chl catabolites by oxidative removal of the formyl group by a P450 enzyme. Here a structural investigation of the DCCs in the methylesterase16 mutant of Arabidopsis thaliana is reported. Eight new DCCs were identified and characterized structurally. Strikingly, three of these DCCs carry stereospecifically added hydroxymethyl groups, and represent bilin‐type linear tetrapyrroles with an unprecedented modification. Indeed, DCCs show a remarkable structural parallel, otherwise, to the bilins from heme breakdown. |
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| Keywords: | Arabidopsis thaliana bilin chlorophyll cytochrome P450 phyllobilin |
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