Energy transfer in allophycocyanin hexamer from Anabaena variabilis by time-resolved spectroscopy

Abstract

The process and mechanism for energy transfer in an allophycocyanin hexamer from Anabaena variabilis have been studied by time-resolved fluorescence spectroscopy. Deconvolution of isotropic time-resolved fluorescence spectra shows that the energy transfer time between two allophycocyanin trimers is about 14 ps, while the energy transfer time from the linker polypeptide (L cm 42) to the final emission is about 65 ps. The anisotropic results of time-resolved fluorescence spectra show that the energy transfer process among three ring-like ( α- 84/ α- 84) chromophore pairs still plays an important role with a time constant of about 45 ps. The facts support the idea that the mechanism for energy transfer in the allophycyanin hexamer should be described by Föster dipole—dipole interaction rather than by an exciton interaction.