Single Molecule Spectroscopy of Oriented Recombinant Trimeric Light Harvesting Complexes of Higher Plants

The bleaching dynamics of reconstituted single light-harvesting chlorophyll a/b investigated. The complexes containing one histidine<INF>6</INF> tag per monomeric subunit were immobilised predominantly in a defined orientation with their symmetry axis perpendicular to a Ni-ion-containing surface allowing for the first time the examination of single LHCIIb in an aqueous environment. Most complexes exhibit photobleaching in one step, indicating coupling between the monomeric subunits leading to an energy transfer between adjacent subunits. Differences in bleaching behaviour between these and previous observations with single LHCIIb are discussed.