ADMR study of the effect of oligomerisation on the carotenoid triplets and on triplet-triplet transfer in light harvesting complex II (LHC II) of spinach

摘要: Carotenoid triplets in isolated light harvesting complex (LHC) II of spinach at different concentrations were studied by absorbance-detected magnetic resonance (ADMR). Going from high to low LHC concentrations, a change was observed the intensity ADMR spectra |D|+|E| transition recorded 507 nm relative that 525 nm, approx. 0.5 1.0. The 2|E| did not change. singla is due signal detected nm. effect ascribed an aggregation trimeric into oligomeric form II. Taking account narrowing zero-field bands with oligomerisation, and absence bandshifts, increase can be explained assuming oligomer consists multiple trimers, between which ‘inter-trimer’ energy transfer occurs. This yields number transferred carotenoid having its triplet absorption maximum Our new results indicate carotenoids are bound Chl monomers, dimers as proposed earlier (Van der Vos, R., Carbonera, D. Hoff, A.J. (1991) Appl. Magn. Res. 2, 179–202).