ARCHITECTURE AND MECHANISM OF THE LIGHT-HARVESTING APPARATUS OF PURPLE BACTERIA

Photosynthetic organisms fuel their metabolism with light energy and h ave developed for this purpose an efficient apparatus for harvesting s unlight. The atomic structure of the apparatus, as it evolved in purpl e bacteria, has been constructed through a combination of x-ray crysta llography, electron microscopy, and modeling. The detailed structure a nd overall architecture reveals a hierarchical aggregate of pigments t hat utilizes, as shown through femtosecond spectroscopy and quantum ph ysics, elegant and efficient mechanisms for primary light absorption a nd transfer of electronic excitation toward the photosynthetic reactio n center.