Login

GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]


Structure and function of photosynthesis protein explained in detail

Photosynthetic complex I is a key element in photosynthetic electron transport, but little has been known about it so far.

An international team of researchers has solved the structure and elucidated the function of photosynthetic complex I. This membrane protein complex plays a major role in dynamically rewiring photosynthesis. The team from the Max Planck Institute for Biochemistry, Osaka University and Ruhr-Universität Bochum together with their collaboration partners report the work in the journal Science. “The results close one of the last major gaps in our understanding of photosynthetic electron transport pathways,” says Associate Professor Dr. Marc Nowaczyk, who heads the Bochum project group “Cyanobacterial Membrane Protein Complexes”.

Biology’s electrical circuits

Complex I is found in most living organisms. In plant cells it is used in two places: one is in mitochondria, the cell’s power plants, the other is in chloroplasts, where photosynthesis occurs. In both instances, it forms part of an electron transport chain, which can be thought of as biology’s electrical circuit. These are used to drive the cells molecular machines responsible for energy production and storage. The structure and function of mitochondrial complex I as part of cellular respiration has been well investigated, whereas photosynthetic complex I has been little studied so far.

Short-circuiting photosynthesis

Using cryoelectron microscopy, the researchers were able to solve for the first time the molecular structure of photosynthetic complex I. They showed that it differs considerably from its respiratory relative. In particular, the part responsible for electron transport has a different structure, since it is optimised for cyclic electron transport in photosynthesis.

Cyclic electron transport represents a molecular short circuit in which electrons are reinjected into the photosynthetic electron transport chain instead of being stored. Marc Nowaczyk explains: “The molecular details of this process have been unknown and additional factors have not yet been unequivocally identified.” The research team simulated the process in a test tube and showed that the protein ferredoxin plays a major role. Using spectroscopic methods, the scientists also demonstrated that the electron transport between ferredoxin and complex I is highly efficient.

Molecular fishing rod

In the next step, the group analysed at the molecular level which structural elements are responsible for the efficient interaction of complex I and ferredoxin. Further spectroscopic measurements showed that complex I has a particularly flexible part in its structure, which captures the protein ferredoxin like a fishing rod. This allows ferredoxin to reach the optimal binding position for electron transfer.

“This enabled us to bring the structure together with the function of the photosynthetic complex I and gain a detailed insight into the molecular basis of electron transport processes,” summarises Marc Nowaczyk. “In the future, we plan to use this knowledge to create artificial electron transport chains that will enable new applications in the field of synthetic biology.”

Read the paper: Science

Article source: Ruhr-Universität Bochum

Image credit: Pixabay License

News

Scientists engineer shortcut for photosynthetic glitch, boost crop growth 40%

Plants convert sunlight into energy through photosynthesis; however, most crops on the planet are plagued by a photosynthetic glitch, and to deal with it, evolved an energy-expensive process called photorespiration that drastically suppresses their yield potential. Researchers from the University of Illinois and U.S. Department of Agriculture Agricultural Research Service report in the journal Science that crops engineered with a photorespiratory shortcut are 40 percent more productive in real-world agronomic conditions.


Should researchers engineer a spicy tomato?

The chili pepper, from an evolutionary perspective, is the tomato's long-lost spitfire cousin. They split off from a common ancestor 19 million years ago but still share some of the same DNA. While the tomato plant went on to have a fleshy, nutrient-rich fruit yielding bountiful harvests, the more agriculturally difficult chili plant went defensive, developing capsaicinoids, the molecules that give peppers their spiciness, to ward off predators.


European wheat lacks climate resilience

The climate is not only warming, it is also becoming more variable and extreme. Such unpredictable weather can weaken global food security if major crops such as wheat are not sufficiently resilient – and if we are not properly prepared.