Open AccessThe functional role of protein in the organization of bacteriochlorophyll c in chlorosomes of Chloroflexus aurantiacus
Author(s) -
NIEDERMEIER Georg,
SCHEER Hugo,
FEICK Reiner G.
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb16682.x
Subject(s) - chlorosome , bacteriochlorophyll , chemistry , crystallography , absorption (acoustics) , biophysics , photochemistry , biochemistry , biology , physics , optics , photosynthesis
The preparation of five different fractions containing bacteriochlorophyll (Bchl) c and their absorption and circular dichroic properties have been described. The fractions investigated were purified chlorosomes, proteolytically modified chlorosomes, chlorosomes treated with lithium dodecyl sulfate (LDS) which were subsequently subjected to size‐exclusion chromatography, in vitro Bchl c aggregates and, additionally, the so‐called GEF chlorosomes [prepared according to Griebenow and Holzwarth (1989) Biochim. Biophys. Acta 973 , 235–240]. Proteolysis of chlorosomes caused a 35–40% decrease in absorption intensity, a 6–8 nm blue shift of the 740‐nm peak and, in particular, a drastic increase of rotational strength as revealed by CD spectroscopy. Although oligomeric Bchl c aggregates and LDS‐treated chlorosomes had absorption characteristics similar to Bchl c in vivo , the data clearly indicated that protein, perhaps the chlorosome‐specific M r ‐3700 polypeptide, was involved in the organization of Bchl c in chlorosomes from C. aurantiacus . Furthermore, the results showed that the LDS‐treated chlorosome fraction was most likely comprised of a micellar complex of Bchl c with LDS which represented an entity entirely different from chlorosomes.