Structures of chlorosomes and aggregated BChlc inChlorobium tepidum from solid state high resolution CP/MAS(13)C NMR.

Cross polarization/magic angle spinning (CP/MAS)(13)C (solid state high resolution) NMR spectra were observed for chlorosomes and BChlc aggregates. Similarity of both kinds of spectra (except for some signals assignable to proteins and lipids in chlorosomes) indicates that BChlc's in chlorosomes are present just as in synthetic BChlc aggregates. Chemical shifts for C13(1) carbonyl and C3(1) hydroxylethyl carbons indicate hydrogen bonding between them. Comparison of solution and solid state(13)C NMR chemical shifts shows the five coordinated nature of BChlc aggregates. Some chemical shift differences were attributable to ring currents shifts. Their comparisons with calculated ring current shift values predicted structures for the aggregates. Cross polarization dynamics of the CP/MAS(13)C NMR signals explored dynamic and structural nature of the BChlc aggregates.