Researchers at TU Graz have gained new insights into the functioning of a protein found in bacteria, whose enzymatic activity is activated by blue light.
Light affects living organisms in many different ways: for example, plants orient their growth direction towards the sun, while circadian rhythms in humans are controlled by daylight. These processes always involve photoreceptors, which are proteins that can sense different colors and intensities of light.
10,000-fold increase in enzymatic activity
Now, researchers at Graz University of Technology (TU Graz) have deciphered the function of a highly efficient photoreceptor. Their findings have been published in the journal Science Advances. The research team studied a diguanylate cyclase protein that is found in many bacteria. Its enzymatic function regulates the production of a central messenger substance that controls the way bacteria live. In darkness, the protein is almost completely inactive, but as soon as it is exposed to blue components of daylight, its enzymatic activity increases rapidly. “The protein’s enzymatic activity is about 10,000 times higher when it is exposed to light than it is in the dark,” said Andreas Winkler, Head of the Photobiochemistry Working Group at TU Graz’s Institute of Biochemistry. In most photoreceptors, activity increases by a factor of between 5 and 50, resulting in more gradual changes in protein activity. “By contrast, the protein that we characterized reacts very strongly,