The Iron and Magnesium Branches of the Porphyrin Biosynthetic Pathway - Chlorophyll Biosynthesis and Technological Applications - page 186

Fig. 6.5 Biosynthetic pathway (Adapted from Rebeiz et al. 2003 ) and depicting the fully
esterified Chl biosynthetic routes. To facilitate understanding of the text, various biosynthetic
routes are designated by the numbers 16-17. All abbreviation are as in Rebeiz et al. ( 2003 )
distance separating the centers of the donor and acceptor molecules. It has been
estimated that dipole-dipole energy transfer between donor and acceptor molecules
may occur up to a separation distance of 50-100 ˚ (Calvert and Pitts 1967 ).
Resonance excitation energy transfer from three tetrapyrrole donors to the Chl
a of Chl-protein complexes were monitored, namely: from Proto, DV Mg-Proto and
its methyl ester and MV and DV Pchlide a . DV Proto is a common precursor of
heme and Chl. It is the immediate precursor of DV Mg-Proto. As such, it is an early
intermediate along the Chl biosynthetic chain. Biosynthetically, it is several steps
removed from the Chl end product. Mg-Proto is a mixed MV-DV, dicarboxylic
tetrapyrrole pool, consisting of DV and MVMg-Proto. It is the precursor of DV and
MV Pchlide a. The protochlorophyll(ide) [(Pchl(ide)] of higher plants consists of