Unusual carotenoid composition and a new type of xanthophyll cycle in plants

The capture of photons by the photosynthetic apparatus is the first step in photosynthesis in all autotrophic higher plants. This light capture is dominated by pigment-containing proteins known as light-harvesting complexes (LHCs). The xanthophyll-carotenoid complement of these LHCs (neoxanthin, vio...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1999-02, Vol.96 (3), p.1135-1139
Main Authors: Bungard, R.A, Ruban, A.V, Hibberd, J.M, Press, M.C, Horton, P, Scholes, J.D
Format: Article
Language:English
Subjects:
Absorption spectra
Biological Sciences
biosynthesis
Botany
Carotenoids
chemical constituents of plants
chlorophyll
Chlorophylls
Cuscuta reflexa
Evolution
Flowers & plants
Fluorescence
Irradiance
light
light harvesting complex
lutein-5,6-epoxide
neoxanthin
Photosynthesis
Pigments
Plant products
Plants
species differences
Spinacia oleracea
Thylakoids
Xanthophylls
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The capture of photons by the photosynthetic apparatus is the first step in photosynthesis in all autotrophic higher plants. This light capture is dominated by pigment-containing proteins known as light-harvesting complexes (LHCs). The xanthophyll-carotenoid complement of these LHCs (neoxanthin, violaxanthin, and lutein) is highly conserved, with no deletions and few, uncommon additions. We report that neoxanthin, considered an integral component of LHCs, is stoichiometrically replaced by lutein-5,6-epoxide in the parasitic angiosperm Cuscuta reflexa, without compromising the structural integrity of the LHCs. Lutein-5,6-epoxide differs from neoxanthin in that it is involved in a light-driven deepoxidation cycle similar to the deepoxidation of violaxanthin in the xanthophyll cycle, which is implicated in protection against photodamage. The absence of neoxanthin and its replacement by lutein-5,6-epoxide changes our understanding of the structure-function relationship in LHCs, has implications for biosynthetic pathways involving neoxanthin (such as the plant hormone abscisic acid), and identifies one of the early steps associated with the evolution of heterotrophy from autotrophy in plants.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.96.3.1135