Abstract
A new procedure was developed for isolation of the chlorosomes from Chl. tepidum by combination of EDTA-lysozyme treatment and osmotic disruption of cells in the presence of 2 M NaSCN, and sucrose density gradient centrifugation. The energy transfer efficiency of the isolated chlorosomes from BChl c to the baseplate BChl a was nearly close to that in whole cells. During the isolation, the absorption maximum of the chlorosomes blue-shifted by about 10 nm from that in whole cells. However, it returned to the original wavelength in the cells after the addition of polyethyleneglycol (PEG) probably due to the hydrophobic effect. The spectral analyses of chlorosomes showed only the long-wavelength spectral form of BChl c aggregates was changed after the addition of PEG. This suggests that BChls c in the chlorosomes changed their aggregation structure during the isolation procedure and BChls c aggregation states are not uniform in the chlorosomes.
