Composition and localization of bacteriochlorophyll a intermediates in the purple photosynthetic bacterium Rhodopseudomonas sp. Rits.
Rhodopseudomonas sp. Rits is a recently isolated new species of photosynthetic bacteria and found to accumulate a significantly high amount of bacteriochlorophyll (BChl) a intermediates possessing non-, di- and tetra-hydrogenated geranylgeranyl groups at the 17-propionate as well as normal phytylated BChl a (Mizoguchi T et al. (2006) FEBS Lett 580:137-143). A phylogenetic analysis showed that this bacterium was closely related to Rhodopseudomonas palustris. The strain Rits synthesizes light-harvesting complexes 2 and 4 (LH2/4), as peripheral antennas, as well as the reaction center and light-harvesting 1 core complex (RC-LH1 core). The amounts of these complexes were dependent upon the incident light intensities, which was also a typical behavior of Rhodopseudomonas palustris. HPLC analyses of extracted pigments indicated that all four BChls a were associated with the purified photosynthetic pigment-protein, as complexes described above. The results suggested that this bacterium could use these pigments as functional molecules within the LH2/4 and RC-LH1 core. Pigment compositional analyses in several purple photosynthetic bacteria showed that such BChl a intermediates were always detected and were more widely distributed than expected. Long chains in the propionate moiety of BChl a would be one of the important factors for assembly of LH systems in purple photosynthetic bacteria.
Harada
Jiro
J
Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Mizoguchi
Tadashi
T
Yoshida
Sayaka
S
Isaji
Megumi
M
Oh-Oka
Hirozo
H
Tamiaki
Hitoshi
H
D025541:Bacteriochlorophyll A / Q000737:chemistry / Q000378:metabolism*; D008027:Light; D010802:Phylogeny; D012241:Rhodopseudomonas / Q000145:classification / Q000254:growth & development / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
D025541:Bacteriochlorophyll A