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Fig. 6.3
Monocarboxylic divinyl Chl
a
and
b
biosynthetic route of DDV-LDV-DLDV plants.
(Adapted from Kolossov and Rebeiz
2010
).
DV
divinyl,
MV
monovinyl,
ALA
δ
-aminolevulinic
acid,
Proto
protoporphyrin IX,
Mpe
Mg-Proto monomethyl ester,
Pchlide
protochlorophyllide;
Chlide
chlorophyllide,
Chl
chlorophyll,
4VMPR
[4-vinyl] Mg-Proto reductase,
4VMpeR
[4-vinyl]
Mg-Proto monoester reductase,
4VPideR
[4-vinyl] protochlorophyllide
a
reductase,
4VCR
[4-vinyl] chlorophyllide
a
reductase,
4VChlR
[4-vinyl] Chl reductase,
POR
Pchlide
a
oxidoreductase.
Arrows
joining DV and MV routes refer to reactions catalyzed by [4-vinyl]
reductases. The new biosynthetic route labeled 0 was called for by the discovery of 4VMpeR. All
other routes are designated by Arabic numerals as described in Rebeiz et al. (
2003
)
6.2.1.2 Spatial Chl Biosynthetic Heterogeneity
As just mentioned, chemical biosynthetic heterogeneity refers to the biosynthesis of
an anabolic tetrapyrrole or end product at several different locations of the thyla-
koid membranes, via different biosynthetic routes, each involving at least one
different enzyme. We recently tested for spatial Chl biosynthetic heterogeneity by
monitoring resonance excitation energy transfer between anabolic tetrapyrrole
intermediates of the Chl biosynthetic pathway and various thylakoid Chl-protein
complexes (Kolossov et al.
2003
).
Fluorescence resonance energy transfer involves the transfer of excited state
energy from an excited donor “D*” to an unexcited acceptor “A” (Calvert and Pitts
1967
; Lakowicz
1999
; Turro
1965
). The transfer is the result of dipole-dipole
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