Tn. Sidorova et al., CHARACTERISTICS OF THE PHOTOSYNTHETIC APPARATUS OF THE PURPLE BACTERIUM THIOCAPSA SP. BM3 CONTAINING OKENONE AS A MAJOR CAROTENOID, Microbiology, 67(2), 1998, pp. 158-164
Photosynthetic apparatus of the purple bacterium Thiocapsa sp. BM3 was
studied. This strain was isolated from an algobacterial mat in a lago
on of the White Sea and, according to data from DNA-DNA hybridization,
represents a new species of the genus Thiocapsa. An LH1-RC ensemble,
LH2 light-harvesting complex, and a fraction of free pigments were iso
lated from the membranes of this bacterium. Investigation of carotenoi
ds showed that the LH1-RC ensemble contained okenone and spirilloxanth
in, whereas the LH2 complex contained only okenone. The fraction of fr
ee pigments contained carotenoids; depending on the type of detergent
used, it could also contain bacteriochlorophyll. In the latter case, t
he absorption spectrum of the fraction was similar to that of the ''ca
rotenoid-containing B820 subcomplex'' isolated from Chromatium purpura
tum. The possible involvement of carotenoids in the assembly of photos
ynthetic complexes is discussed.