Chlorophyll breakdown in senescent banana leaves: catabolism reprogrammed for biosynthesis of persistent blue fluorescent tetrapyrroles.
Bottom Line: Amazingly, in the leaves of banana plants, persistent hmFCCs were identified that accounted for about 80 % of the chlorophyll broken down, and yellow leaves of M. acuminata display a strong blue luminescence.The structures of eight hmFCCs from banana leaves were analyzed by spectroscopic means.As expressed earlier in related studies, the present findings call for attention, as to still elusive biological roles of these linear tetrapyrroles.
Affiliation: Institute of Organic Chemistry & Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck (Austria).Show MeSH
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Mentions: The now known FCCs and NCCs from higher plants are bilin-type linear tetrapyrroles that reflect an oxygenolytic opening of the macrocycle of chlorophyll a at the northern α-meso-position, with retention of the meso carbon as a formyl group.[4, 5] These chlorophyll catabolites may be classified as formyloxobilins,[5, 10] as—except for their additional and characteristic substituted cyclopentanone ring—they display similar structural features as the heme-derived (dioxo)bilins.[14, 15] In most senescent leaves studied, NCCs have been found to accumulate.[4, 16] In addition, dioxobilin-type nonfluorescent chlorophyll catabolites (DNCCs) have been identified in some leaves,[8, 17] that is, linear tetrapyrroles that have lost their formyl group[17–19] (Figure 1). The natural dioxobilin-type chlorophyll catabolites resemble heme catabolites in higher plants remarkably closely.
Affiliation: Institute of Organic Chemistry & Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck (Austria).