Blue Light Receptors
Another class of natural photoreceptors are blue light receptors. They absorb mainly in the blue and near UV spectral region and often employ flavin based chromophores. like AppA or Phototropin.
In collaboration with the group of Joachim Heberle (Biophysical Chemistry, University of Bielefeld) we investigate the domain LOV1 (Light Oxygen Voltage) of the Phototropin 1 protein of the green algae Chlamydomonas Reinhardtii. Phototropin is a protein commonly found in plants, which regulates several aspects of photosynthesis, like phototropic plant movement, chloroplast movement and opening of stomata. The domain LOV1 is the photosensitive subunit of the protein. It contains the chromophore FMN, which forms a covalent bond with a cystein group of the protein within several µs after photoexcitation.
Ultrafast Spectroscopy in the infrared and in the visible is used to investigate the processes which prelude bond formation. This includes changes in the electronic and geometric structure of the chromophore and the reaction of the protein to this changes.