The capacity of chlorophyll-a biosynthesis in the mustard seedling cotyledons as modulated by phytochrome and circadian rhythmicity

Planta ◽  
1977 ◽  
Vol 133 (3) ◽  
pp. 295-302 ◽  
Author(s):  
H. Gehring ◽  
H. Kasemir ◽  
H. Mohr
Keyword(s):  
Chlorophyll A ◽  
Circadian Rhythmicity ◽  
Mustard Seedling ◽  
Chlorophyll A Biosynthesis

Chlorophyll a biosynthesis

1976 ◽  
Vol 273 (924) ◽  
pp. 207-225 ◽  
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Chlorophyll Synthesis ◽  
Synthesis Reaction ◽  
Etiolated Leaves ◽  
Regulatory Aspects ◽  
Vinyl Group ◽  
Chlorophyll A Biosynthesis ◽  
Monomethyl Ester

Protoporphyrin IX is believed to be an intermediate common to both haem and chlorophyll biosynthesis. The pathway specific to chlorophyll starts with magnesium protoporphyrin and its monomethyl ester. Two routes have been proposed for conversion of the latter compound to protochlorophyllide: A, formation of the isocyclic ring followed by reduction of the 4-vinyl group, or B, reduction of the 4-vinyl group followed by formation of the isocyclic ring. Membranes prepared from isolated barley etioplasts are found to convert magnesium 2,4-divinylphaeoporphyrin a 5 monomethyl ester to chlorophyllide a at a rate equal to that of chlorophyll synthesis in intact leaves: this result supports route A. NADPH is necessary to maintain the two successive reductive steps: reduction of the 4-vinyl group and then the photoreduction of ring IV to yield chlorophyllide. The prohaem content of etiolated leaves does not increase during the phase of active chlorophyll synthesis although evidence is presented that suggests that the ALA synthesis reaction that regulates chlorophyll synthesis is common to both pathways. This and other regulatory aspects are discussed.

The Esterification of Chlorophyllide a in Greening Bean Leaves

1978 ◽  
Vol 33 (9-10) ◽  
pp. 712-714 ◽  
Author(s):  
Siegrid Schoch
Keyword(s):  
Chlorophyll A ◽  
White Light ◽  
Dark Period ◽  
Chl A ◽  
Chlorophyll A Biosynthesis ◽  
Bean Leaves

Abstract The accumulation of esterfied chlorophyll a (Chl a) in etiolated bean leaves was determined during a dark period of 60 minutes after 1 minute irradiation with white light. The separation of the pigments esterified with geranylgeraniol (GG), dihydrogeranylgeraniol (DHGG), tetrahydrogeranylgeraniol (THGG) and phytol (P) was performed by HPLC. The last step for chlorophyll a biosynthesis is confirmed to be an esterification of chlorophyllide a to ChlGG followed by a stepwise hydrogenation of the pigment-bounded alcohols to ChlDHGG and ChlTHGG and finally to Chl a.

scholarly journals 8-vinyl reduction and chlorophyll a biosynthesis in higher plants

1993 ◽  
Vol 291 (3) ◽  
pp. 939-944 ◽  
Author(s):  
B J Whyte ◽  
W T Griffiths
Keyword(s):  
Triticum Aestivum ◽  
Chlorophyll A ◽  
Redox State ◽  
Higher Plants ◽  
Solid Phase ◽  
Compositional Analysis ◽  
The Individual ◽  
Vinyl Reductase ◽  
Kinetics Of ◽  
Chlorophyll A Biosynthesis

A technique involving solid-phase extractions and polyethylene h.p.l.c. suitable for the routine compositional analysis of the total protochlorophyllide pool of plants is described. The resynthesis kinetics of the individual components of the pool have been studied in briefly illuminated etiolated tissue of wheat (Triticum aestivum) and cucumber (Cucumis sativus) during subsequent redarkening. The data are interpreted in terms of a precursor-product relationship between the di- and mono-vinyl analogues of protochlorophyllide during their reaccumulation in darkness. The interconversion is assumed to be catalysed by an 8-vinyl reductase, which shows greater activity in wheat than in cucumber. Analyses of the redox state of the nicotinamide nucleotide of the pool during the process are compatible with NADPH as the cofactor of the putative reductase.

High-Resolution electron crystallography of the light-harvesting chlorophyll-a/b protein complex from chloroplast membranes

1990 ◽  
Vol 48 (1) ◽  
pp. 610-610
Author(s):  
Werner Kühlbrandt ◽  
Da Neng Wang ◽  
K.H. Downing
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Chlorophyll A ◽  
Protein Complex ◽  
Structural Integrity ◽  
Light Harvesting ◽  
Lhc Ii ◽  
Diffraction Patterns ◽  
Difference Fourier ◽  
2D Crystals

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

Identification of a single-copy gene encoding a Type I chlorophyll a/b-binding polypeptide of photosystem I in Arabidopsis thaliana

1992 ◽  
Vol 84 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Poul E. Jensen ◽  
Michael Kristensen ◽  
Tine Hoff ◽  
Jan Lehmbeck ◽  
Bjarne M. Stummann ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Single Copy ◽  
Type I ◽  
Single Copy Gene ◽  
Gene Encoding ◽  
Copy Gene
Sign in / Sign up

Export Citation Format

Share Document