Persistent Hole Burning Study of Core Antenna of Photosystem

The application of hole burning spectroscopy (HB) in the study of photosynthetic systems offers an independent method for determining excited state lifetimes of particular chromophores. The rate constants of excitation energy transfer (EET) in photosynthetic antennae can be directly determined by time resolved fluorescence spectroscopy. For most bacterial and higher plants antennae is of the order of 10 to the -12 power/s. Efficient EET in pigment-protein complexes causes significant shortening (three orders of magnitude) of the excited state lifetimes T sub 1 in comparison with isolated pigments. The hole widths obtained in hole burning spectroscopy are proportional to the total relaxation time T sub 2: 1/T sub 2 = 1/2T sub 1 + 1/T sub 2*. In the presence of fast EET the T sub 1 contribution is dominant. The aim of this report is to compare the role of protein environment and efficiency of EET in photosystem II (PS II) core antenna chlorophyll protein complex (CPa2) in polyacrylamid gel with that of the core antenna in native PS II particles in buffer/glycerol glass (PS II part.).