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Chlorophyll breakdown in senescent banana leaves: catabolism reprogrammed for biosynthesis of persistent blue fluorescent tetrapyrroles.

Vergeiner C, Banala S, Kräutler B - Chemistry (2013)

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.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry & Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck (Austria).

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Abbreviated structural outline of chlorophyll breakdown in senescent leaves and ripening fruits.[5] Chlorophylls (Chl a and b) are degraded to primary fluorescent chlorophyll catabolites (pFCC, or its C-1 epimer, epi-pFCC).[9, 24] FCCs with free propionic acid groups isomerize spontaneously by an acid-catalyzed reaction to the corresponding nonfluorescent chlorophyll catabolites (NCCs),[12] such as Hv-NCC-1.[4, 25] FCCs esterfied at the propionic acid group are persistent, such as Mc-FCC-56, a hypermodified FCC (hmFCC) in peels of ripe banana.[20–22] In an alternative path, dioxobilin-type nonfluorescent chlorophyll catabolites result from deformylation at ring B, such as Ap-DNCC from senescent leaves of Norway maple.[18, 26]
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fig01: Abbreviated structural outline of chlorophyll breakdown in senescent leaves and ripening fruits.[5] Chlorophylls (Chl a and b) are degraded to primary fluorescent chlorophyll catabolites (pFCC, or its C-1 epimer, epi-pFCC).[9, 24] FCCs with free propionic acid groups isomerize spontaneously by an acid-catalyzed reaction to the corresponding nonfluorescent chlorophyll catabolites (NCCs),[12] such as Hv-NCC-1.[4, 25] FCCs esterfied at the propionic acid group are persistent, such as Mc-FCC-56, a hypermodified FCC (hmFCC) in peels of ripe banana.[20–22] In an alternative path, dioxobilin-type nonfluorescent chlorophyll catabolites result from deformylation at ring B, such as Ap-DNCC from senescent leaves of Norway maple.[18, 26]

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.[18]


Chlorophyll breakdown in senescent banana leaves: catabolism reprogrammed for biosynthesis of persistent blue fluorescent tetrapyrroles.

Vergeiner C, Banala S, Kräutler B - Chemistry (2013)

Abbreviated structural outline of chlorophyll breakdown in senescent leaves and ripening fruits.[5] Chlorophylls (Chl a and b) are degraded to primary fluorescent chlorophyll catabolites (pFCC, or its C-1 epimer, epi-pFCC).[9, 24] FCCs with free propionic acid groups isomerize spontaneously by an acid-catalyzed reaction to the corresponding nonfluorescent chlorophyll catabolites (NCCs),[12] such as Hv-NCC-1.[4, 25] FCCs esterfied at the propionic acid group are persistent, such as Mc-FCC-56, a hypermodified FCC (hmFCC) in peels of ripe banana.[20–22] In an alternative path, dioxobilin-type nonfluorescent chlorophyll catabolites result from deformylation at ring B, such as Ap-DNCC from senescent leaves of Norway maple.[18, 26]
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig01: Abbreviated structural outline of chlorophyll breakdown in senescent leaves and ripening fruits.[5] Chlorophylls (Chl a and b) are degraded to primary fluorescent chlorophyll catabolites (pFCC, or its C-1 epimer, epi-pFCC).[9, 24] FCCs with free propionic acid groups isomerize spontaneously by an acid-catalyzed reaction to the corresponding nonfluorescent chlorophyll catabolites (NCCs),[12] such as Hv-NCC-1.[4, 25] FCCs esterfied at the propionic acid group are persistent, such as Mc-FCC-56, a hypermodified FCC (hmFCC) in peels of ripe banana.[20–22] In an alternative path, dioxobilin-type nonfluorescent chlorophyll catabolites result from deformylation at ring B, such as Ap-DNCC from senescent leaves of Norway maple.[18, 26]
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.[18]

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.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry & Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck (Austria).

Show MeSH
Related in: MedlinePlus