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

Fluorescence lifetime measurements with nanometer spatial resolution a re made possible by incorporating time-correlated single photon counti ng with a near-field fluorescence microscope. Using this apparatus, si ngle pieces of intact photosynthetic membrane from the Chlamydomonas r einhardtii strain doubly deficient in photosystem I (PS I) and photosy stem II (PS II) are examined. Comparison of simultaneous force and emi ssion images shows single membrane bilayers lying flat on the mica sub strate with the embedded light harvesting complex (LHC II) proteins ag gregated isotropicly across the membrane imaged. Fluorescence lifetime s are measured at a single spot on the membrane with picosecond time r esolution.