MIAMI.- Research led by the University of Oxford, United Kingdom, discovered that Rubisco, the enzyme that powers all life on Earth, is not stuck in an evolutionary rut as previously thought, on the contrary it improves all the time although it does in a very slow way.
This finding could potentially open new routes to strengthen food security. The results were published in Proceedings of the National Academy of Sciences (PNAS).
The most abundant enzyme on Earth provides the energy that fuels life on our planet for the last 3 billion years. While Rubisco fixes billions of tons of CO2 each year, the enzyme has been considered notoriously inefficient. This has created a biological paradox that has baffled researchers for decades.
The enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase, more commonly known by the short name RuBisCO or simply Rubisco, catalyzes the first important step in carbon fixation.
The most abundant protein
Rubisco is the most abundant protein in the world, as it is present in every plant that undergoes photosynthesis and molecular synthesis. It makes up up to 20-25% of the soluble protein in the leaves. They estimate that each person on Earth is supported by about 44 kg of Rubisco.
Many plant scientists have debated for several years whether the enzyme is stuck in an “evolutionary rut,” making it impossible to improve. But new research from the University of Oxford has revealed that it is continually improving, but it is happening at a very slow rate.
Lead author Jacques Bouvier, a PhD student in Oxford’s Department of Biology, said in a statement: “Our research demonstrates for the first time that evolution is constantly improving and it is possible to continue improving the enzyme. Importantly, this information “provides renewed optimism for efforts to engineer the enzyme to help feed the world.”
Slow but safe
The researchers analyzed sequences of the Rubisco gene from a wide range of photosynthetic organisms and quantified the rate of evolution of the enzyme for the first time.
They found that its sequence has been altered in tiny increments of just one base change every 900,000 years, a stark contrast to the COVID-19 genome, for example, which evolves one base change every two weeks.
This places Rubisco in the 1% of the slowest evolving genes on Earth, but despite this slow rate of change, the researchers found that the enzyme is taking advantage of this evolution to improve CO2 fixation. The authors also discovered that this slowly progressing CO2 fixation is resulting in progress in photosynthesis; Plants are evolving in their ability to convert CO2 into sugar, but the pace of improvement is so slow that it seems frozen.
For decades, scientists have aspired to engineer an improved Rubisco to boost the growth and yield of crop plants. But despite many efforts, success has been limited.
Renewed hope
However, the insights from this study offer renewed hope. In particular, unraveling the mystery of what is slowing the rate of evolution of the enzyme may uncover new ways to improve crop yields.
Jacques Bouvier added: “Given that Rubisco assimilates the sugars that fuel life on Earth, improving this enzyme is one of the most promising avenues to help combat food insecurity. There has been heated debate about whether there is scope to optimize the enzyme; our new research provides a clear answer to this question.”
This new knowledge provides encouragement to efforts aimed at increasing the yield of food, fiber and fuel crops by focusing on Rubisco engineering. Improving the most abundant protein enzyme in the biosphere could be key to meeting the food needs of a growing global population
Source: Europa Press /Infobae /Editorial Diario las Américas
