2001; Alia et al. 2001, 2004; van Gammeren et al. 2004, 2005a, b; Ganapathy et al. 2007) and reaction center complexes (Prakash et al. 2005; Diller et al. 2007; Daviso et al. 2008; Alia et al. 2009) have been GSK2399872A solubility dmso resolved with atomic resolution using MAS NMR in conjunction with stable-isotope labeling. Very recently, the structure of a member of the chlorosome class of Pexidartinib mouse light-harvesting antennae was determined and compared with the wild type (WT) to resolve how the biological light-harvesting function of the chlorosome is established, an important step on the way to artificial photosynthesis
(Ganapathy et al. 2009). This article is devoted to summarize the research into the direction of comprehensive protein assessment using the LH2 antenna system as a model protein using MAS NMR. First, a brief theoretical background of the MAS NMR technique is presented. Subsequently, a variety of model experiments performed
by MAS NMR for LH2 complex will be discussed to illustrate the versatility of MAS NMR as a biophysical technique in photosynthesis. Theoretical background MAS NMR is a technique for obtaining high resolution NMR data from solids. For an extensive introduction to the technique, the reader is referred to the existing literature (Duer 2004). This section serves to guide the interested student to this background literature. Contrary to solution NMR, where anisotropic interactions are averaged by the rapid tumbling of molecules, in solid-state NMR, interactions such as
the FK228 chemical shift and dipolar coupling dominate. As a consequence, the spectral line width of nuclei in solids is Idoxuridine rather broad. In order to overcome this problem in the solid state, MAS NMR is applied. In MAS NMR, a sample is rotated rapidly around an axis at the magic angle θ m = 54.74° with the static field (Andrew et al. 1958; Lowe 1959) to effectively suppress chemical shift broadening. In order to describe the MAS NMR experiment, the Hamiltonian $$ H = H_\textCS + H_\textD^IS + H_\textD^II $$ (1)is used. \( H_\textCS \) is the chemical shielding term, \( H_\textD^IS \) represents the heteronuclear dipolar couplings, and \( H_\textD^II \) describes the homonuclear dipolar couplings. The chemical shielding affects the NMR frequency, which is determined by the Zeeman interaction $$ H_ 0 = – \mu \cdot \mathbfB_ 0 , $$ (2)between a nuclear magnetic moment μ and the external static magnetic field \( \mathbf\bf B_ 0 \). The μ can be expressed in terms of the nuclear spin operator I as \( \mu = \gamma \hbar \mathbfI_{{}} \), and Eq. 2 can be rewritten as $$ H_ 0 = – \gamma \hbar I_z B_ 0 .