Scientists have discovered a bacterium that can “eat” sunlight and “breathe” out oxygen.
In a recently published article in the journal Science Advances, the research team demonstrated how this mysterious organism harvests light energy.
Microscopic image of Gemmatimonas phototrophica. (Photo: Jason Dean, Czech Academy of Sciences).
The researchers utilized electron microscope images collected from four different laboratories. Their study revealed the detailed structure of the photosynthetic complex, which includes 178 pigments linked to over 80 protein subunits of this microorganism. The light-harvesting subunits are arranged in two concentric rings around a reaction center, converting absorbed light energy into electrical charges.
Associate Professor Michal Koblizek from the Institute of Microbiology at the Czech Academy of Sciences stated that this microorganism is a true masterpiece of nature. “It not only has good structural stability but also a high efficiency in light harvesting.”
While we are familiar with many photosynthetic bacteria, what occurs in the Gobi Desert, where Gemmatimonas phototrophica resides, is unique.
Diagram of two multicolored molecular rings surrounding a central circle of the photosynthetic complex from Gemmatimonas phototrophica. (Photo: Dr. Tristan I. Croll, University of Cambridge, UK).
Because the pigments in the outer ring have higher energy than those in the center, the entire arrangement acts like a funnel. The energy absorbed by the pigments at the periphery of this complex is transferred to the center, where it is converted into metabolic energy.
Although this photosynthetic structure may require more energy compared to other familiar types, the researchers explain, “in return, this structure possesses extraordinary stability, and the durability of this photosynthetic complex may represent an evolutionary advantage.”
Dr. Pu Qian, a structural biologist at the University of Sheffield, remarked: “This structural and functional study is intriguing as it shows that G. phototrophica has independently developed its own compact, robust, and highly efficient architecture to harvest and ‘trap’ solar energy.”
One day, we may also be able to unlock the secrets of the ancient photosynthetic process of G. phototrophica to build a future of synthetic biology that harnesses solar energy.
