Attempts are being made to model the plant's light-harvesting and water-splitting megamachinery property to study small-molecule photosynthesis process. Researchers are building scaled-down versions of the plant's photosystem II (PSII), a 20-protein machine that captures sunlight using pigments and funnels the excitation energy into its reaction centers. Simple systems made of porphyrin donors are being built, which are more stable relatives of chlorophyll, the primary lightharvesting pigment in plant's photosystem II (PSII). The Arizona State University has designed a variety of artificial photosynthetic systems, with light-gathering anthracene-based antennas attached to an electron-donating porphyrin and an electron-accepting fullerene. Researchers are also aimed to integrate the lightharvesting apparatus and the water-oxidation catalyst by using a ruthenium-based system that harvests light and drives the oxidation of a dimanganese unit.