Wednesday, February 1, 2012

Plant enzyme gathers energy day and night

Plants are renown for their capability of creating energy out of sunlight; a process called photosynthesis. At night, there is no sun which means the energy creating process lays dormant. However, plants appear to have an enzyme that does not only aid in photosynthesis during the day, but also gathers energy during the night. During its night shift, it aids in taking up nutrients and transporting energy from the roots. It is peculiar how one particular enzyme can have two distinctive functions, which depend on time of day.

Building blocks
Michigan State University researchers discovered that an enzyme called ATP synthase achieves its dual function by exchanging a building block. Enzymes are proteins, and proteins are made out of a chain of amino acids, that fold in a specific way. By switching one of the amino acids, they found that ATP synthase can perform two distinct functions.

ATP synthase has a specific form for each of its functions. When the scientists blocked one form, they found that the plant could no longer perform photosynthesis. Blocking the second version, however, caused a disruption in the uptake of nutrients and transport of energy in the plant's root. Thereafter, the researchers created a genetically modified plant that made a lot of ATP synthase in the latter form, which resulted in larger outgrowths from the root, ones that are used to soak up material from the ground.

While it is unclear what the benefits are of knowing this, it certainly is interesting to note that one particular enzyme has two radically different functions. Even more striking is that only a small change is sufficient to achieve this duality. Because photosynthesis is not possible during the night, perhaps plants developed a way to use the required machinery for other energy related tasks. Because the scientists also found that ATP synthase plays a role in regulating the level of photosynthesis, the next step will be to find out way to increase its efficiency. That may make plants easier to grow, which is beneficial for us. But it does not seem likely we will find a practical use any time soon.

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