TY  - JOUR
AU  - Matsubara, S.
AU  - Morosinotto, T.
AU  - Osmond, C. B.
AU  - Bassi, R.
TI  - Short- and long-term operation of the lutein-epoxide cycle in light-harvesting antenna complexes
JO  - Plant physiology
VL  - 144
SN  - 0032-0889
CY  - Rockville, Md.: Soc.
PB  - JSTOR
M1  - PreJuSER-56263
SP  - 926 - 941
PY  - 2007
N1  - Record converted from VDB: 12.11.2012
AB  - The lutein-5,6-epoxide (Lx) cycle operates in some plants between lutein (L) and its monoepoxide, Lx. Whereas recent studies have established the photoprotective roles of the analogous violaxanthin cycle, physiological functions of the Lx cycle are still unknown. In this article, we investigated the operation of the Lx cycle in light-harvesting antenna complexes (Lhcs) of Inga sapindoides Willd, a tropical tree legume accumulating substantial Lx in shade leaves, to identify the xanthophyll-binding sites involved in short- and long-term responses of the Lx cycle and to analyze the effects on light-harvesting efficiency. In shade leaves, Lx was converted into L upon light exposure, which then replaced Lx in the peripheral V1 site in trimeric Lhcs and the internal L2 site in both monomeric and trimeric Lhcs, leading to xanthophyll composition resembling sun-type Lhcs. Similar to the violaxanthin cycle, the Lx cycle was operating in both photosystems, yet the light-induced Lx --> L conversion was not reversible overnight. Interestingly, the experiments using recombinant Lhcb5 reconstituted with different Lx and/or L levels showed that reconstitution with Lx results in a significantly higher fluorescence yield due to higher energy transfer efficiencies among chlorophyll (Chl) a molecules, as well as from xanthophylls to Chl a. Furthermore, the spectroscopic analyses of photosystem I-LHCI from I. sapindoides revealed prominent red-most Chl forms, having the lowest energy level thus far reported for higher plants, along with reduced energy transfer efficiency from antenna pigments to Chl a. These results are discussed in the context of photoacclimation and shade adaptation.
KW  - Adaptation, Physiological
KW  - Carotenoids: metabolism
KW  - Chlorophyll: metabolism
KW  - Fabaceae: metabolism
KW  - Light-Harvesting Protein Complexes: metabolism
KW  - Lutein: analogs & derivatives
KW  - Lutein: metabolism
KW  - Photosystem I Protein Complex: metabolism
KW  - Plant Leaves: metabolism
KW  - Recombinant Proteins: metabolism
KW  - Spectrum Analysis
KW  - Sunlight
KW  - Thylakoids: metabolism
KW  - Time Factors
KW  - Light-Harvesting Protein Complexes (NLM Chemicals)
KW  - Photosystem I Protein Complex (NLM Chemicals)
KW  - Recombinant Proteins (NLM Chemicals)
KW  - lutein-5,6-epoxide (NLM Chemicals)
KW  - Lutein (NLM Chemicals)
KW  - Chlorophyll (NLM Chemicals)
KW  - Carotenoids (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:17384157
C2  - pmc:PMC1914152
UR  - <Go to ISI:>//WOS:000247075000036
DO  - DOI:10.1104/pp.107.099077
UR  - https://juser.fz-juelich.de/record/56263
ER  -