Experts unlock key to photosynthesis, a find that could help us meet food security demands
Scientists
have solved the structure of one of the key components of photosynthesis, a
discovery that could lead to photosynthesis being 'redesigned' to achieve
higher yields and meet urgent food security needs.
The
study, led by the University of Sheffield and published today in the journal Nature,
reveals the structure of cytochrome b6f -- the protein complex that
significantly influences plant growth via photosynthesis.
Photosynthesis
is the foundation of life on Earth providing the food, oxygen and energy that
sustains the biosphere and human civilisation.
Using
a high-resolution structural model, the team found that the protein complex
provides the electrical connection between the two light-powered
chlorophyll-proteins (Photosystems I and II) found in the plant cell
chloroplast that convert sunlight into chemical energy.
Lorna
Malone, the first author of the study and a PhD student in the University of
Sheffield's Department of Molecular Biology and Biotechnology, said: "Our
study provides important new insights into how cytochrome b6f utilises the
electrical current passing through it to power up a 'proton battery'. This
stored energy can then be then used to make ATP, the energy currency of living
cells. Ultimately this reaction provides the energy that plants need to turn
carbon dioxide into the carbohydrates and biomass that sustain the global food
chain."
The
high-resolution structural model, determined using single-particle
cryo-electron microscopy, reveals new details of the additional role of
cytochrome b6f as a sensor to tune photosynthetic efficiency in response to
ever-changing environmental conditions. This response mechanism protects the
plant from damage during exposure to harsh conditions such as drought or excess
light.
Dr
Matt Johnson, reader in Biochemistry at the University of Sheffield and one of
the supervisors of the study added: "Cytochrome b6f is the beating heart
of photosynthesis which plays a crucial role in regulating photosynthetic
efficiency.
"Previous
studies have shown that by manipulating the levels of this complex we can grow
bigger and better plants. With the new insights we have obtained from our
structure we can hope to rationally redesign photosynthesis in crop plants to
achieve the higher yields we urgently need to sustain a projected global population
of 9-10 billion by 2050."
The
research was conducted in collaboration with the Astbury Centre for Structural
Molecular Biology at the University of Leeds.
Researchers
now aim to establish how cytochrome b6f is controlled by a myriad of regulatory
proteins and how these regulators affect the function of this complex.
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