A new mimic system of photosymhetic apparatus was constructed from C-phycocyanin and phthalocyanine zinc. C-FC was solubilized in the reverse micelles of non ionic surfactant Tween-80, cosurfactant pentanol, and solvent cyclohexane, in which the overall concentration of surfactant was 20% (w/v) and the mass ratio of Tween-80 to pentanol was 4:1. When the molar ratio of water to Tween-80 (R w)?S9.0, the characteristic properties of C-PC were maintained. When it was excited, the energy transfer from C-PC to phthalocyanine zinc took place. The energy transfer efficiency was only related with the concentration of phthalocyanine, but not that of C-PC. Furthermore, the energy transfer was roughly in keeping with Perrin formulation, which indicated that the energy transfer took place approximately through dipole-dipole interaction in rigid system. The radii of the quenching sphere were calculated from the experimental results. For example, when the concentration of phthalocyanine zinc was 2.10×10-4 mol/L, the radius of the quenching sphere of the system was 10.9 nm.
The antenna system of algae for photosynthesis is a functional entity composed of various phycobiliproteins and the linker polypeptides. Up to now, high-resolution crystal structure data have been available only for the isolated phycohiliproteins. To have an understanding of the functional connection between different phycobiliproteins, it is necessary to study the complexes composed of different phycobiliproteins. The energy transfer processes in C-phycocyanin complexes were studied through computer simulation because it is dificult to be studied by conventional experimental methods. The main pathways of energy flow and the dynamic property of the energy transfer were obtained. A fast transfer process between two neighboring disks was observed through analyzing the distribution curves of excitation energy over time. According to the definition of the time constants for energy transfer in time-resolved spectrum techniques, for a complex with three C-phycocyanin hexamer disks, a fluorescence-rising component with several picoseconds was obtained in disk 2 and 20 ps in disk 3 when the chromophores in disk 1 were excited by an ideal Δ pulsed laser beam. The results showed clearly that the energy transfer between the disks in an antenna rod was very fast and that energy transfer was fast and efficient in an intact antenna system of algae.
