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 two slightly less polar FCCs, Ma-FCC-63 and Ma-FCC-64, could be separated (in part) by preparative HPLC in MeOH/H2O (see the Experimental Section). The first separation was incomplete due to partial interconversion of these isomeric hmFCCs (see below). For the second, final purification step corresponding precautions were taken to prevent isomerization and possible transesterification (with methanol) by changing the solvent system to ACN/H2O and by running HPLC with shorter on-column times. The FCC containing fractions were directly frozen in liquid nitrogen, stored at −80 °C to avoid isomerization. The samples were lyophilized, to yield 0.79 mg (0.98 μmol) of analytical pure Ma-FCC-63, and 0.63 mg (0.77 μmol) of Ma-FCC-64, to be used for spectroscopic analyses. The UV/Vis spectra of the two FCCs as well as their CD spectra showed considerable similarities; these spectra were also comparable to those of Ma-FCC-69 (Figure 4).
Affiliation: Institute of Organic Chemistry & Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck (Austria).