Direct measurement of excitation transfer dynamics between two trimers in C-phycocyanin hexamer from cyanobacterium Anabaena variabilis

We provide the first experimental evidence for the excitation transfers between two trimers of an isolated C-phycocyanin hexamer (αβ)6PCLRC27, at the end of the rod proximal to the core of PBS in cyanobacterium of Anabaena variabilis, with picosecond time-resolved fluorescence spectroscopy. Our results strongly suggest that the observed fluorescence decay constants around 20 and 10 ps time scales, shown in anisotropy decay, not in isotropic decay experiments arose from the excitation transfers between two trimers via two types of transfer pathways such as 1β155↔6β155 (2β155↔5β155 and 3β155↔4β155) and 2α84↔5α84 (3α84↔6α84 and 1α84↔4α84) channels and these could be described by Föster dipole-dipole resonance mechanism.