Non-linear spectroscopy of carotenoid-chlorophyll interactions in photosynthetic light-harvesting complexes

Abstract

In addition to chlorophylls a and b light-harvesting complex (LHC II) binds xanthophylls. Nonlinear polarization spectroscopy in the frequency domain (NLPF) was used to investigate the changes in the interactions between xanthophylls and chlorophylls in LHC II upon alteration of its aggregation state. Additionally, two-photon excitation profiles in the xanthophylls presumed 11Ag− → 21Ag− transition region were measured of LHC II samples containing different xanthophyll complements, as well as of chlorophylls a and b in solution. Implications of the results for recently proposed mechanism(s) of qE/NPQ will be discussed.