Kinetics of energy transfer processes in C-phycocyanin complexes

The antenna system of algae for photosynthesis is a functional entity compo sed of various phycobiliproteins and the linker polypeptides. Up to now, hi gh-resolution crystal structure data have been available only for the isola ted phycobiliproteins. To have an understanding of the functional connectio n between different phycobiliproteins, it is necessary to study the complex es composed of different phycobiliproteins. The energy transfer processes i n C-phycocyanin complexes were studied through computer simulation because it is difficult to be studied by conventional experimental methods. The mai n pathways of energy now and the dynamic property of the energy transfer we re obtained. A fast transfer process between two neighboring disks was obse rved through analyzing the distribution curves of excitation energy over ti me. According to the definition of the time constants for energy transfer i n time-resolved spectrum techniques, for a complex with three C-phycocyanin hexamer disks, a fluorescence-rising component with several picoseconds wa s obtained in disk 2 and 20 ps in disk 3 when the chromophores in disk 1 we re excited by an ideal delta 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.