A team of researchers has found out how the ‘Shethna protein II’ shields the nitrogen-fixing enzyme nitrogenase from harm. This oxygen-sensing protein might make nitrogenase applicable in biotechnology, which could help lessen reliance on synthetic fertilizers.
Researchers from the University of Freiburg, under the guidance of biochemist Prof. Dr. Oliver Einsle, have revealed the protective role of the “Shethna protein II” for the nitrogen-fixing enzyme nitrogenase. This discovery could pave the way for the use of nitrogenase in biotechnology, potentially decreasing the need for synthetic fertilizers. Their findings have been shared in the journal Nature.
A small yet crucial player: an oxygen sensor protein that protects the intricate system of biological nitrogen fixation from significant harm. Its potential applications in biotechnology could lead to decreased reliance on synthetic fertilizers in future agricultural practices. Professors Dr. Oliver Einsle and his team from the Faculty of Chemistry and Pharmacy and the Centre for Biological Signalling Studies (BIOSS) at the University of Freiburg have thoroughly investigated how the so-called Shethna protein II operates, utilizing advanced cryo-electron microscopy techniques. Their results have been documented in the journal Nature.
Ecological Issues with Nitrogen Fertilizers
Nitrogen is a vital element for all forms of life and is commonly added to crops as fertilizer to enhance long-term yields. However, the methods of producing and using these fertilizers are environmentally and energetically concerning. For years, scientists have been trying to apply the natural nitrogen-fixing capabilities of certain bacteria and archaea to agricultural crops. The nitrogenase enzyme plays a critical role in this nitrogen binding process. One of the significant challenges in incorporating nitrogenase into plants is its extreme sensitivity to oxygen, which is generated by plants themselves during photosynthesis.
Shethna Protein II Interacts with Nitrogenase
Philipp Franke, Simon Freiberger, and Dr. Lin Zhang, part of Prof. Einsle’s team, have demonstrated how the Shethna protein II detects increased oxygen levels. It swiftly forms a protective complex with the two parts of the nitrogenase enzyme, safeguarding them from oxidative harm. This activated Shethna protein II tightly binds the larger nitrogenase and its related reductase, creating long filaments that prevent oxygen from reaching the active sites of the nitrogenase. Once the cells manage to handle this oxidative stress, the complex disbands, allowing the enzyme to continue functioning.
Potential Applications in Plant Cells
Even if nitrogenase is produced within plant cells, it is expected that temporary spikes in oxygen levels will continue to pose challenges. In biotechnological contexts, co-producing the Shethna protein II could help shield these intricately produced enzymes in their new environments, ensuring their functionality within plant cells. “Successfully producing functional nitrogenase in plants would revolutionize green biotechnology, and this small protein could play a crucial role in enabling that,” explains Einsle.
- Prof. Dr. Oliver Einsle is a biochemistry professor at the Faculty of Chemistry and Pharmacy and part of the Centre for Biological Signalling Studies (BIOSS) at the University of Freiburg. His research focuses on the structure, function, and development of complex enzyme systems. Philipp Franke, Simon Freiberger, and Dr. Lin Zhang are part of his research group.
- The project received funding from the European Union through an ERC Advanced Grant for Prof. Dr. Oliver Einsle and support from the German Research Foundation (DFG) as part of the Collaborative Research Centre ‘Dynamic Organization of Cellular Protein Machineries’.
