Scientists uncover a novel mechanism that regulates carbon dioxide fixation...( A team of Biotechnology and Biologic...)

A team of Biotechnology and Biological Sciences Research Council (BBSRC) funded scientists at the University of Essex has discovered a new mechanism that slows the process of carbon dioxide fixation in plants.

The research, published today (4 March 2008) in the Proceedings of the National Academy of Sciences, increases our understanding of this process, which may ultimately lead to crop improvement and fourth generation biofuels. The mechanism, which helps to regulate the way in which plants absorb carbon dioxide (CO2) from the atmosphere and turn it into sugars, acts by putting the brakes on sugar production when there is not enough energy from sunlight available. As sunlight increases, the brakes are rapidly released and carbon dioxide fixation speeds away.

Plants are dependent on sunlight to capture carbon dioxide, which is turned into important sugars via a process called the Calvin cycle. As a result, as the amount of sunlight varies during the day (e.g. through cloud cover or shading from other plants), they must also be able to vary the speed at which they capture carbon dioxide from the atmosphere. This ensures that when there is a lot of sunlight, it is taken full advantage of but that when sunlight drops, so does CO2 uptake. This ability to maximise energy use is important for plants and prevents the loss of important metabolic resources. Because they essentially stay in one place, plants must have many unique abilities to adapt to their environment as it changes around them.

The question is how does this variable speed control actually work" The BBSRC-funded research shows for the first time how the Calvin cycle can be regulated in response to a changing light environment via a molecular mechanism. There is a special relationship between two enzymes that are involved in the Calvin cycle phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). When light levels decrease, the two enzymes tend to stic
'/>"/>