The primary objective in the Larsen laboratory is to understand the different ways that Nature converts photon energy into useful biological function. This entails identifying and characterizing, on a molecular level, the protein-cofactor interactions that result in biological function with particular emphasis on the role of dynamical processes. The ultimate goal is not only to describe how proteins function, but to understand the underlying mechanisms to a degree that new proteins can be constructed to possess or perform desired functions.

Evolution has fine-tuned the properties of protein environments to optimize specific aspects of embedded reactions (e.g. the use of energy "funnels" to harvest sunlight in photosynthetic light harvesting complexes and the specific use of unique electron transfer pathways in bacterial reaction centers). Proteins use these evolutionary adaptations to alter intra-protein reactions through both structural and dynamical processes. Even though the influence of the structural properties to these reactions have been extensively investigated with X-ray scattering and NMR studies, the function of protein dynamical effects in controlling these reactions is still poorly understood. Using non-linear, time-resolved spectroscopic techniques in conjunction with molecular dynamics simulations, we characterize the specific protein motions responsible for influencing the photo-induced activity. The interplay of simulations and experiment provides for a novel, detailed study of the factors responsible for affecting biological reactions and hence biological functions.

Systems studied:

    Phytochromes

    Photoactive Yellow Protein

    Green Fluorescence Proteins

    Retinal Binding Proteins