Role of Xanthophylls in Light Harvesting in Green Plants: A Spectroscopic Investigation of Mutant LHCII and Lhcb Pigment–Protein Complexes

Abstract

The spectroscopic properties and energy transfer dynamics of the protein-bound chlorophylls and xanthophylls in monomeric, major LHCII complexes, and minor Lhcb complexes from genetically altered <i>Arabidopsis thaliana</i> plants have been investigated using both steady-state and time-resolved absorption and fluorescence spectroscopic methods. The pigment–protein complexes that were studied contain Chl <i>a</i>, Chl <i>b</i>, and variable amounts of the xanthophylls, zeaxanthin (Z), violaxanthin (V), neoxanthin (N), and lutein (L). The complexes were derived from mutants of plants denoted <i>npq1</i> (NVL), <i>npq2lut2</i> (Z), <i>aba4npq1lut2</i> (V), <i>aba4npq1</i> (VL), <i>npq1lut2</i> (NV), and <i>npq2</i> (LZ). The data reveal specific singlet energy transfer routes and excited state spectra and dynamics that depend on the xanthophyll present in the complex