Scientists have uncovered high-resolution images of photosynthetic protein complexes in bacteria, offering new insights that could revolutionize clean energy systems.
Scientists at the University of Liverpool, in collaboration with several international institutions, have made significant strides in understanding bacterial photosynthesis. By employing state-of-the-art cryogenic electron microscopy, they have captured detailed structural images of key photosynthetic protein complexes in purple bacteria, specifically Rhodobacter blasticus.
These findings, published in the journal Science Advances, could propel advancements in artificial photosynthetic systems crucial for sustainable energy production.
Bacterial photosynthesis, akin to plant photosynthesis, enables certain microorganisms to convert light into energy. This process is vital to the global nutrient cycles, energy flow in ecosystems, and forms a foundational element of aquatic food chains. Insights into this ancient process also provide valuable understanding of life’s evolution on Earth.
The research team, comprising experts from the University of Liverpool, the Ocean University of China, Huazhong Agricultural University and Thermo Fisher Scientific, successfully imaged both monomeric and dimeric forms of the photosynthetic reaction centre-light harvesting complexes (RC-LH1) from R. blasticus.
The unique “flat” dimeric structure unveiled by their study distinguishes R. blasticus from its close relatives among purple bacteria, showcasing the adaptability and variability in bacterial photosynthetic systems.
“By revealing these natural photosynthetic mechanisms, we open new avenues for designing more efficient light-harvesting and energy transduction systems or cells,” Luning Liu, a professor and chair of microbial bioenergetics and bioengineering at the University of Liverpool, said in a news release. “This study represents a significant step forward in our comprehension of how bacteria optimize their photosynthetic machinery, providing valuable insights that could inform future clean energy innovations.”
This breakthrough is notably marked by the absence of a protein component called PufY in the RC-LH1 structure of R. blasticus.
Instead, the bacteria compensate with additional light-harvesting subunits creating a more enclosed LH1 structure, impacting electron transport rates and energy transfer efficiency. The dimeric form’s flatter conformation suggests specific adaptations for membrane curvature and energy transfer efficiency, differing from other model species.
“Our findings demonstrate the structural diversity of photosynthetic complexes even among closely related bacterial species,” added Liu. “This variability likely reflects different evolutionary adaptations to specific environmental conditions. We are thrilled that we can contribute such molecular details in the investigation of photosynthetic mechanisms and evolution.”
The multi-faceted approach of this study, combining structural biology, in silico simulations and spectroscopic studies, is key in uncovering the sophisticated assembly and electron transfer mediation in bacterial photosynthetic complexes. These insights not only advance scientific knowledge but also hold promising implications for creating highly efficient artificial photosynthetic systems, which could be instrumental in developing clean, renewable energy solutions.