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 sugar moieties of Ma-FCC-63 and Ma-FCC-64 were further characterized as glucopyranose units, based on analysis of the values of the 1H,1H coupling constants within the two pyranose units, NOE correlations from 1H,1H ROESY spectra and of the 1H and 13C chemical shift data (Figure 6), and comparison with those of reference compounds.[33–36] Indeed, these two (slowly interconverting) FCCs were thus deduced to differ only by the stereochemistry at their anomeric centers. Accordingly, Ma-FCC-63 was identified as a 31,32-didehydro-82-hydroxy-132-(methoxycarbonyl)-173-(6′-β-glucopyranosyl)-1,4,5,10,17,18,20,22-octahydro-4,5-seco-(22H)-phytoporphyrin, and Ma-FCC-64 as the 173-(6′-α-glucopyranosyl) anomer.
Affiliation: Institute of Organic Chemistry & Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck (Austria).