Activation in photoresponsive proteins occurs in different steps: a first “ultrafast” photochemical reactions triggers a cascade of conformational changes, which lead to an active form of the protein.
In our recent article, published Open Access in the Journal of the American Chemical Society, we investigated the activation of a carotenoid-containing photoresponsive protein, Orange Carotenoid Protein of cyanobacteria. Our Molecular Dynamics simulations reveal the molecular mechanism leading to the activation. The protein-bound carotenoid glues together the two domains of the protein; after the photoexcitation, the carotenoid slides into the N-terminal domain, allowing the protein to open and reach the active state.
