CHAPTER 25: Magic Angle Spinning NMR Spectroscopy for Resolving Structure and Mechanisms of Function of Membrane Protein Assemblies Involved in Photosynthetic Energy Conversion

This chapter summarizes recent developments in biological solid-state NMR for the study of supramolecular organization, energy landscapes, energy conversion and signal transduction in photosynthetic systems. Following a brief description of magic angle spinning and relevant homonuclear recoupling schemes, RFDR, PDSD, DARR, and CHHC, their performance in photosynthesis studies is illustrated with investigations of LHCII light harvesting antenna complexes and the chlorosomal CsmA baseplate protein. Photo-CIDNP is introduced as a versatile technique to study mechanisms of charge separation in the bacterial reaction centre. Subsequent ab initio quantum-mechanical simulations of the special pair with its closest surrounding predicted formation of a strong charge transfer intermediate upon excitation and allowed demonstration of the protein rearrangement assisting the primary charge separation process.