Origin of the chlorophyll b formyl oxygen in Chlorella vulgaris

Chlorophyll (Chl) b is an accessory light-harvesting pigment of plants and chlorophyte algae. Chl b differs from Chl a in that the 3-methyl group on ring B of Chl a is replaced by a 3-formyl group on Chl b. The present study determined the biosynthetic origin of the Chl b formyl oxygen in in vivo la...

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Bibliographic Details
Published in:Biochemistry (Easton) 1992-12, Vol.31 (47), p.11677-11683
Main Authors: Schneegurt, Mark A, Beale, Samuel I
Format: Article
Language:English
Subjects:
Analytical, structural and metabolic biochemistry
Biological and medical sciences
Chlorella - chemistry
CHLORELLA VULGARIS
Chlorophyll - chemistry
Chlorophyll - isolation & purification
CHLOROPHYLLE
CLOROFILAS
ESPECTROMETRIA
Fundamental and applied biological sciences. Psychology
Heterocyclic compounds, pigments
LUMIERE
LUZ
Mass Spectrometry
Molecular Structure
Molecular Weight
OBSCURIDAD
OBSCURITE
Other biological molecules
OXIGENO
Oxygen - chemistry
Oxygen Isotopes
OXYGENE
PROTEINAS
PROTEINE
SPECTROMETRIE
Spectrophotometry
Tetrapyrrolic pigments
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Summary:Chlorophyll (Chl) b is an accessory light-harvesting pigment of plants and chlorophyte algae. Chl b differs from Chl a in that the 3-methyl group on ring B of Chl a is replaced by a 3-formyl group on Chl b. The present study determined the biosynthetic origin of the Chl b formyl oxygen in in vivo labeling experiments. A mutant strain of the unicellular chlorophyte Chlorella vulgaris, which can not synthesize Chls when cultured in the dark but rapidly greens when transferred to the light, was grown in the dark for several generations to deplete Chls, and then the cells were transferred to the light and allowed to form Chls in a controlled atmosphere containing (18)O2. Chl a and Chl b were purified from the cells and analyzed by high-resolution mass spectroscopy. Analysis of the mass spectra indicated that over 76% of the Chl a molecules had incorporated an atom of (18)O. For Chl b, 58% of the molecules had incorporated an atom of (18)O at one position and 34% of the molecules had incorporated an atom of (18)O at a second position. These results demonstrate that the isocyclic ring keto oxygen of both Chl a and Chl b, as well as the formyl oxygen of Chl b, is derived from O2
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00162a002