In the photosynthetic membrane, protein nanomachines work together for the conversion of sunlight into biochemical energy. The photosynthetic machinery continuously adapts to fluctuating environmental light-intensity conditions in order to avoid photodamage at the water-splitting catalytic site of Photosystem II. To understand the molecular mechanisms of photosynthesis, atomic-resolution structures are central for describing the photophysical and photochemical functions. In natural photosynthesis, these functions are tightly integrated with regulatory processes on a larger scale involving molecular plasticity of photosynthetic multi-units and their supramolecular rearrangements in a dynamic, cellular network.
Manipulation of photoregulatory mechanisms can be a rational means for enhancing photosynthetic productivity of crop growth or algae biofuels 1,2. This approach is held back by the lack of high-resolution structural data describing the fundamentals of photoregulation by the interplay of atomic and (supra)molecular interactions in an active, biological membrane. Solid-state NMR holds great promise as key technique for this purpose.
By solid-state NMR, large biomolecules can be studied at atomic resolution and under near-native conditions without need for crystallization. MRI and HR-MAS NMR developments allow micro-imaging and metabolic profiling of intact systems. Together the techniques have the exciting potential to attain a high-resolution structural view of regulatory processes inside the photosynthetic machinery. To realize this goal, we develop NMR methods for solving structure and plasticity inside large photosystems, design novel membrane models to view their behavior in native-like environments and develop isotope-labeling approaches for photosynthetic organisms. To relate structure to function, NMR methods are complemented with optical spectroscopy and advanced modeling approaches.
1 PG Stephenson, CM Moore, MJ Terry, MV Zubkov and TS Bibby Improving photosynthesis for algal biofuels: toward a green revolution, Trends in Biotechnology 2011, Vol. 29, No. 12 DOI: 10.1016/j.tibtech.2011.06.005
2 EH Murchie and KK Niyogi Manipulation of Photoprotection to Improve Plant Photosynthesis, Plant Physiology 2011, Vol. 155, pp. 86–92 DOI: 10.1104/pp.110.168831