Controls on Chlorophyll Synthesis in Barley
Kenneth D. Nadler,S. Granick +1 more
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TLDR
A model for control of chlorophyll synthesis is proposed, based on a light-induced activation at the translational level of the synthesis of proteins forming delta-aminolevulinic acid, as well as the short half-life of these proteins.Abstract:
In 7- to 10-day-old leaves of etiolated barley (Hordeum vulgare), all of the enzymes that convert δ-aminolevulinic acid to chlorophyll are nonlimiting during the first 6 to 12 hours of illumination, even in the presence of inhibitors of protein synthesis. The limiting activity for chlorophyll synthesis appears to be a protein (or proteins) related to the synthesis of δ-aminolevulinic acid, presumably δ-aminolevulinic acid synthetase. Protein synthesis in both the cytosol and plastids may be required to produce nonlimiting amounts of δ-aminolevulinic acid. The half-life of a limiting protein controlling the synthesis of δ-aminolevulinic acid appears to be about 1½ hours, when determined with inhibitors of protein synthesis. Acceleration of chlorophyll synthesis by light is not inhibited by inhibitors of nucleic acid synthesis, but is inhibited by inhibitors of protein synthesis. A model for control of chlorophyll synthesis is proposed, based on a light-induced activation at the translational level of the synthesis of proteins forming δ-aminolevulinic acid, as well as the short half-life of these proteins. Evidence is presented confirming the idea that the holochrome on which protochlorophyllide is photoreduced to chlorophyllide functions enzymatically.read more
Citations
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Journal ArticleDOI
FLU: a negative regulator of chlorophyll biosynthesis in Arabidopsis thaliana.
TL;DR: In Arabidopsis thaliana, a negative regulator of tetrapyrrole biosynthesis is found, FLU, which operates independently of heme and seems to selectively affect only the Mg2+ branch of Tetrapyr Role biosynthesis.
Journal ArticleDOI
Phytochrome-induced appearance of mRNA activity for the apoprotein of the light-harvesting chlorophyll a/b protein of barley (Hordeum vulgare).
TL;DR: It is concluded that the change in mRNA activity is controlled by phytochrome and the possible role of the phy to chrome-induced appearance of mRNA activity as a rate-limiting step of the greening process is discussed.
Journal ArticleDOI
Biosynthesis of delta-aminolevulinic acid from the intact carbon skeleton of glutamic acid in greening barley.
TL;DR: Demonstration of the new pathway in plants has been made by feeding specifically labeled [14C]glutamic acid to etiolated barley shoots greening in the light, and the labeling pattern for delta-aminolevulinic acid is consistent with a biosynthetic route utilizing the intact five-carbon skeleton of alpha-ketoglutarate, glutamate, or glutamine.
Journal ArticleDOI
Light Regulation of Chlorophyll Biosynthesis at the Level of 5-Aminolevulinate Formation in Arabidopsis
L L Ilag,Anuj Kumar,Dieter Söll +2 more
TL;DR: Arabidopsis genes that encode the enzymes of the C5 pathway via functional complementation of mutations in the corresponding genes of E. coli were isolated and RNA gel blot analyses indicated that transcripts for both genes are found in root, leaf, stem, and flower tissues and that their levels are dramatically elevated by light.
References
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