Magic Angle Spinning NMR of Photosynthetic Components

Abstract

Selectively and multispin labelled cofactors, ligands, amino acids and proteins can be prepared and used for investigations with MAS NMR to determine structure and mechanisms of function of biological systems. In particular, solid state crosspolarization (CP) MAS NMR dipolar correlation spectroscopy is a rapidly growing technique that can provide structural information of systems that are inaccessible for X-ray diffraction techniques [1]. In our research programme, a principal application of the MAS NMR is in the studies of photosynthetic energy conversion systems. In terms of spin-off, the elucidation of the functional concepts behind photosynthetic charge separation in nature is expected to be of assistance in improving artificial photosynthetic devices like photovoltaic cells. Photosynthesis is the process that converts solar energy into chemical energy, thus providing the earth’s major renewable energy resources. Development of renewable energy supplies is an urgent need from economic, strategic and environmental perspectives. Current official guidelines and industrial programmes put a strong emphasis on biomass, which is from a fundamental scientific perspective a giant technological leap backwards since only a few percent of the solar energy is converted (Table I). Although the actual application of artificial molecular solar energy converters may still be years ahead, elucidation of physical and chemical concepts behind Nature’s efficient primary processes in photosynthetic energy conversion, such as optimal compartmentation of light-harvesting and photochemical energy conversion devices, balance between charge separation and neutral spin separation, will be of use to photovoltaics and molecular electronics research.