Aa. Moskalenko et al., PIGMENT-PROTEIN COMPLEXES FROM CHROMATIUM-MINUTISSIMUM AFTER EXTRACTION OF CAROTENOIDS, Biochemistry, 59(9), 1994, pp. 1049-1053
Up to 50% of carotenoids were selectively extracted with benzene from
the membranes of Chromatium minutissimum. Extraction of carotenoids di
d not influence the spectral properties of the membranes. These membra
nes treated with n-octyl glucoside (OG)(3) were separated by PAGE into
three bands, which represented: 1) partially destroyed B880-RC assemb
ly with preserved carotenoids which limited the dissociation of B880 c
omplex into subunits; 2) a new blue band which is the carotenoid-free
B812 subcomplex (a subunit of the B880 complex) according to spectral
characteristics and polypeptide composition. The re-associated B812 co
mplex, as compared to the analogous complex from non-sulfur bacteria,
revealed unusual properties: appearance of two forms of bacteriochloro
phyll (Bchl) at 796 nm and 845-847 nm, absence of fluorescence of the
two forms of Bchl, stability in the presence of ionic detergents; 3) l
ight-harvesting B800-B850 complex, partially depleted of carotenoids (
up to 40%). Larger conformational changes were characteristic of this
complex in the presence of non-ionic detergent as compared to the cont
rol.