Composition and localization of bacteriochlorophyll a intermediates in the purple photosynthetic bacterium Rhodopseudomonas sp. Rits

Abstract

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.

The 17-propionate esterifying variants of bacteriochlorophyll-a and bacteriopheophytin-a in purple photosynthetic bacteria

“…The present results obtained from whole cells of purple bacteria were consistent with those from the isolated LHs and RCs of some Rps. palustris species (CGA009, Morita and Rits strains) [17,18], indicating that both BChl-a and BPhe-a esterified with GG, DHGG and THGG in mature cells were not mere Table S1.…”

“…palustris species and analyzed their BChl-a and BPhe-a in terms of the 17-propionate ester groups [17], since the organisms accumulated BChl-a and BPhe-a intermediates esterified with GG, DHGG and THGG in a remarkable quantity [18,19]. As a result, the isolated LHs and RCs contained such BChl-a and BPhe-a intermediates in distinct amounts in addition to the usual Phy esters.…”

Chlorophyllide a Oxidoreductase Works as One of the Divinyl Reductases Specifically Involved in Bacteriochlorophyll a Biosynthesis

“…R. sphaeroides J001 and R. palustris J002 strains were rifampicin-resistant derivatives from R. sphaeroides 2.4.1 (26) and R. palustris CGA009 (27), respectively, and used as wild type strains in this study. These bacteria were grown in liquid or on solid PYS media (27) at 30°C under aerobically and semiaerobically dark conditions for genetic manipulations and pigment analyses, respectively, or anaerobi- cally illuminated conditions for phototrophic growth. The Escherichia coli strains, DH5␣ (28), JM109 -pir (29), and S17-1 -pir (30), were grown in liquid or on solid LB media at 37°C.…”

“…These peaks were assigned to BChls a carrying a geranylgeranyl (peak 2), dihydrogeranylgeranyl (peak 3), or tetrahydrogeranylgeranyl group (peak 4) in the 17-propionate residues in the order of elution. The assignment of these three BChl a components was established in our previous studies (26,27). The function of BciB could not be clarified using the dB strain, as in the situation of BciA using the dA strain.…”

Reduction Processes in Biosynthesis of Chlorophyll Molecules: Chemical Implication of Enzymatically Regio- and Stereoselective Hydrogenations in the Late Stages of Their Biosynthetic Pathway

“…Some photosynthetic purple bacteria accumulate bacteriochlorophylls-a possessing GG, DHGG, THGG groups as well as a phytyl group. 62,63 From the cultured cells of one of the above strains, each pigment was separated by HPLC and analyzed by 1 H/ 13 C NMR spectroscopy. 64 The four isolated species were confirmed and their molecular structures were identified.…”