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Xanthophylls of the major photosynthetic light‐harvesting complex of plants: identification, conformation and dynamics
Author(s) -
Ruban Alexander V.,
Pascal Andrew A.,
Robert Bruno
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01799-3
Subject(s) - neoxanthin , xanthophyll , lutein , chemistry , trimer , light harvesting complex , absorption (acoustics) , monomer , resonance raman spectroscopy , photochemistry , circular dichroism , molecule , absorption spectroscopy , resonance (particle physics) , raman spectroscopy , biophysics , crystallography , zeaxanthin , photosynthesis , carotenoid , biochemistry , photosystem ii , biology , optics , dimer , physics , organic chemistry , polymer , particle physics
The electronic transitions of lutein and neoxanthin in the major light‐harvesting complex, LHCIIb, have been identified for the first time. It was found that 0–0, 0–1 and 0–2 transitions of neoxanthin were located around 486, 457 and 430 nm, whilst those for lutein were dependent on the oligomerisation state. For the monomer, the absorption bands of lutein were found at 495, 466 and 437 nm. Trimerisation caused a decrease in lutein absorption and the parallel appearance of an additional absorption band around 510 nm, which was identified by resonance Raman excitation spectra to originate from lutein. Circular dichroism measurements together with analysis of the ν 4 resonance Raman region of xanthophylls suggested that this lutein molecule is distorted in the trimer. This feature is not predicted by the LHCIIb atomic model of Kühlbrandt and co‐workers [Kühlbrandt, W., Wang, D.N. and Fugiyoshi, Y. (1994) Nature 367, 614–621] and is an important step in understanding pigment dynamics of the complex. Oligomerisation of trimers led to a specific distortion of the neoxanthin molecule. These observations suggest that the xanthophylls of LHCIIb sense the protein conformation and which may reflect their special role in the assembly and function of the light‐harvesting antenna of higher plants.