NEAR-FIELD FLUORESCENCE IMAGING AND FLUORESCENCE LIFETIME MEASUREMENT OF LIGHT-HARVESTING COMPLEXES IN INTACT PHOTOSYNTHETIC MEMBRANES

Fluorescence lifetime measurements with nanometer spatial resolution are made possible by incorporating time-correlated single photon counting with a near-field fluorescence microscope. Using this apparatus, single pieces of intact photosynthetic membrane from the Chlamydomonas reinhardtii strain doubly deficient in photosystem I (PS I) and photosystem II (PS II) are examined. Comparison of simultaneous force and emission images shows single membrane bilayers lying flat on the mica substrate with the embedded light harvesting complex (LHC II) proteins aggregated isotropicly across the membrane imaged. Fluorescence lifetimes are measured at a single spot on the membrane with picosecond time resolution.