DISSOCIATION AND RECONSTITUTION STUDIES BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF THE LIGHT HARVESTING COMPLEX OF RHODOSPIRILLUM-RUBRUM

Dissociation and reconstitution of light harvesting complex (LHC) of Rhodospirillum rubrum have been performed with dimethyl sulfoxide. Reconstituted LHC in the presence of five fold excess of free bacteriochlorophyll a (BChl a) or analogues were separated by gel filtration high performance liquid chromatography. Reconstitution was followed by measuring the respective quantities of bound pigments, peak amplitudes of the near infrared band, ratios of monomer to dimer bands in the presence or absence of competing BChl a. Most of the tested derivatives (BChl a(p) esterified with phytol, pyro BChl a, 13(2) hydroxy BChl a, Bchl b, Chl a, Chl b) bind to LHC proteins, but only some of them (BChl a(p), BChl b) are maintained in such a geometry that they can dimerize, giving red-shifted absorption bands.