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Analysis in vitro of the enzyme CRTISO establishes a poly-cis-carotenoid biosynthesis pathway in plants.
Year:
2004
Source of publication :
Plant physiology (source)
Authors :
Isaacson, Tal
;
.
Volume :
136
Co-Authors:
Isaacson, T., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Ohad, I., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Beyer, P., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Hirschberg, J., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Facilitators :
From page:
4246
To page:
4255
(
Total pages:
10
)
Abstract:
Most enzymes in the central pathway of carotenoid biosynthesis in plants have been identified and studied at the molecular level. However, the specificity and role of cis-trans-isomerization of carotenoids, which occurs in vivo during carotene biosynthesis, remained unresolved. We have previously cloned from tomato (Solanum lycopersicum) the CrtISO gene, which encodes a carotene cis-trans-isomerase. To study the biochemical properties of the enzyme, we developed an enzymatic in vitro assay in which a purified tomato CRTISO polypeptide overexpressed in Escherichia coli cells is active in the presence of an E. coli lysate that includes membranes. We show that CRTISO is an authentic carotene isomerase. Its catalytic activity of cis-to-trans isomerization requires redox-active components, suggesting that isomerization is achieved by a reversible redox reaction acting at specific double bonds. Our data demonstrate that CRTISO isomerizes adjacent cis-double bonds at C7 and C9 pairwise into the trans-configuration, but is incapable of isomerizing single cis-double bonds at C9 and C9'. We conclude that CRTISO functions in the carotenoid biosynthesis pathway in parallel with zeta-carotene desaturation, by converting 7,9,9'-tri-cis-neurosporene to 9'-cis-neurosporene and 7'9'-di-cis-lycopene into all-trans-lycopene. These results establish that in plants carotene desaturation to lycopene proceeds via cis-carotene intermediates.
Note:
Related Files :
carotenoids
Genetics
metabolism
molecular genetics
Molecular Sequence Data
plant
Plants
transgenic organism
Show More
Related Content
More details
DOI :
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
26781
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:25
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Scientific Publication
Analysis in vitro of the enzyme CRTISO establishes a poly-cis-carotenoid biosynthesis pathway in plants.
136
Isaacson, T., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Ohad, I., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Beyer, P., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Hirschberg, J., Departments of Genetics , The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Analysis in vitro of the enzyme CRTISO establishes a poly-cis-carotenoid biosynthesis pathway in plants.
Most enzymes in the central pathway of carotenoid biosynthesis in plants have been identified and studied at the molecular level. However, the specificity and role of cis-trans-isomerization of carotenoids, which occurs in vivo during carotene biosynthesis, remained unresolved. We have previously cloned from tomato (Solanum lycopersicum) the CrtISO gene, which encodes a carotene cis-trans-isomerase. To study the biochemical properties of the enzyme, we developed an enzymatic in vitro assay in which a purified tomato CRTISO polypeptide overexpressed in Escherichia coli cells is active in the presence of an E. coli lysate that includes membranes. We show that CRTISO is an authentic carotene isomerase. Its catalytic activity of cis-to-trans isomerization requires redox-active components, suggesting that isomerization is achieved by a reversible redox reaction acting at specific double bonds. Our data demonstrate that CRTISO isomerizes adjacent cis-double bonds at C7 and C9 pairwise into the trans-configuration, but is incapable of isomerizing single cis-double bonds at C9 and C9'. We conclude that CRTISO functions in the carotenoid biosynthesis pathway in parallel with zeta-carotene desaturation, by converting 7,9,9'-tri-cis-neurosporene to 9'-cis-neurosporene and 7'9'-di-cis-lycopene into all-trans-lycopene. These results establish that in plants carotene desaturation to lycopene proceeds via cis-carotene intermediates.
Scientific Publication
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