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Recent publications

  • Summary

    In this study, using high-resolution cryo-electron microscopy, the structure and evolution of a key step in photosynthesis was investigated.

    The goal was to understand precisely how electrons are transferred between proteins during photosynthesis. In the algae Chlamydomonas reinhardtii, the protein cytochrome c₆ (Cyt c₆) is responsible for transporting electrons to photosystem I (PSI), while in plants, plastocyanin performs this role. From an evolutionary perspective, it is assumed that Cyt c₆ originally interacted with PSI and was later increasingly replaced by plastocyanin due to selective pressure. Even today, some cyanobacteria use only cytochrome c₆, some can switch between plastocyanin and Cyt c₆, and higher plants use only plastocyanin.

    Investigating these processes has been difficult because the contact between the proteins is extremely short-lived. Cryo-electron microscopy has now enabled researchers to demonstrate in detail how the binding occurs: Negatively charged sites on Cyt c₆ are used for interaction with PSAF (a part of photosystem I) – similar to plastocyanin. Furthermore, the specific amino acid R66 – which is absent in plastocyanin but present in cyanobacteria – plays a central role in binding to and electron transfer from PSAF to PSI.

    This study thus provides a rare insight into the interaction of ancestral proteins with photosystem I and offers a structural model for their evolution.

  • Summary

    Chloroplasts are the green powerhouses inside plant and algae cells that carry out photosynthesis. In RobuCop, we are exploring ways to redesign these tiny cellular factories to make chloroplasts more efficient, resilient, and productive. But so far, progress has been slow because there aren’t many genetic tools available, and working with plants takes a lot of time and effort.
    To speed things up, we turned the alga Chlamydomonas reinhardtii as a test platform, a lab prototype for chloroplast engineering. We created a fully automated system that can quickly make, manage, and analyze thousands of genetically modified algal strains at once. 
    We expanded the toolbox by adding new selection markers (to identify successful genetic changes) and reporter genes (to track gene activity), and we tested over 140 different genetic parts like switches (promoters), signal sequences, and elements that help control protein production. These parts were designed to be compatible with standard molecular biology methods, making them easy to use and share.
    Using this system, we successfully designed new synthetic promoters and even built a synthetic version of a metabolic pathway in the chloroplast - specifically one involved in photorespiration, a process that normally "wastes" energy in plants. When we introduced this redesigned pathway, the algae grew three times more biomass, showing real potential for boosting productivity.
    In short, this work creates a fast, reliable, and standardized platform for testing and improving chloroplast functions. This approach could be easily adapted to other plants, including important crops, paving the way for smarter, more sustainable agriculture in the future.

  • Summary

    Alarmone molecules called (p)ppGpp are important signals inside plant chloroplasts as they help controlling genes, how proteins are made, and how chloroplasts develop, especially when the plant (or algae) is under stress or lacks nutrients. While we already know that those molecules are important, we still don’t fully understand how they work at the molecular level.
    In this study, it was found that (p)ppGpp attaches to specific parts of two key proteins in the chloroplast’s protein transport system: the SRP and its partner FtsY. These proteins normally work together using GTP (an energy source) to move proteins to their correct locations. But (p)ppGpp blocks this process by competing with GTP, stopping the two proteins from joining properly.
    It was also investigated how (p)ppGpp binds to FtsY and discovered, it uses the same spot as GTP, but with a special phosphate group that physically hinders the two proteins forming a working complex and therefore, stops them from boosting each other's activity. 
    In short, this research gives us the first clear picture of how (p)ppGpp controls a vital protein transport system in plants—helping them respond to stress and changes in their environment.

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