STRUCTURES OF CHLOROSOMES AND AGGREGATED BCHL-C IN CHLOROBIUM-TEPIDUMFROM SOLID-STATE HIGH-RESOLUTION CP MAS C-13 NMR/

Cross polarization/magic angle spinning (CP/MAS) C-13 (solid state hig h resolution) NMR spectra were observed for chlorosomes and BChl c agg regates. Similarity of both kinds of spectra (except for some signals assignable to proteins and lipids in chlorosomes) indicates that BChl c's in chlorosomes are present just as in synthetic BChl c aggregates. Chemical shifts for C13(1) carbonyl and C3(1) hydroxylethyl carbons i ndicate hydrogen bonding between them. Comparison of solution and soli d state C-13 NMR chemical shifts shows the five coordinated nature of BChl c aggregates. Some chemical shift differences were attributable t o ring currents shifts. Their comparisons with calculated ring current shift values predicted structures for the aggregates. Cross polarizat ion dynamics of the CP/MAS C-13 NMR signals explored dynamic and struc tural nature of the BChl c aggregates.