Molecular Dynamics Simulations of Pigment-Protein Assemblies in Photosynthetic Antenna Complexes

Protein-protein interactions govern molecular-scale energy transfer processes in photosynthetic organisms. In the green sulfur bacteria, Chlorobaculum tepidum, light is harvested in large membrane-bound complexes and then funneled in a cascading process through the baseplate CsmA and Fenna-Matthews-Olson (FMO) pigment-protein complexes before reaching the photosynthetic reaction center. However, the nature of the interaction between the baseplate protein and FMO has largely eluded researchers. We present protein-protein docking simulations to derive initial conformations of the CsmA-FMO assembly, and molecular dynamics simulations of the most likely conformations of the proteins in their simulated native environment. Finally, we present implications for the use of these assemblies in biohybrid devices for efficient solar energy utilization.