Polychromatic solar energy conversion in pigment-protein chimeras that unite the two kingdoms of (bacterio)chlorophyll-based photosynthesis

Natural photosynthesis can be divided between the chlorophyll-containing plants, algae and cyanobacteria that make up the oxygenic phototrophs and a diversity of bacteriochlorophyll-containing bacteria that make up the anoxygenic phototrophs. Photosynthetic light harvesting and reaction centre proteins from both groups of organisms have been exploited in a wide range of biohybrid devices for solar energy conversion, solar fuel synthesis and a variety of sensing technologies, but the energy harvesting abilities of these devices are limited by each protein’s individual palette of (bacterio)chlorophyll, carotenoid and bilin pigments. In this work we demonstrate a range of genetically-encoded, self-assembling photosystems in which recombinant plant light harvesting complexes are covalently locked with reaction centres from a purple photosynthetic bacterium, producing macromolecular chimeras that display mechanisms of polychromatic solar energy harvesting and conversion not present in natural systems. Our findings illustrate the power of a synthetic biology approach in which bottom-up construction of a novel photosystem using naturally disparate but mechanistically complementary components is achieved in a predictable fashion through the genetic encoding of adaptable, plug-and-play covalent interfaces. ToC image