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Isolation and characterization of photosynthetic complexes from photoheterotrophic bacteria
Řádek, Martin ; Wilhelmová, Naďa (referee) ; Kučera, Tomáš (advisor)
Aerobic anoxygenic phototrophs (AAPs) represent a relatively recently discovered unique BChl a-containing bacterial community. These organisms own a fully functional bacterial photosynthetic system. Their photosynthesis is operative only in the presence of oxygen. However, they are not able to grow autotrophically, they require a source of organic carbon for growth and metabolism. I have characterized the photosynthetic apparatus of Erythrobacter sp. NAP1, Roseobacter sp. COL2P and the strains Dor-2m, Dor-vul and Zun-kholbo. BChl a performs the function of the main light-harvesting pigment. Spheroidenone is the major carotenoid of the strains COL2P, Dor-2m, Dor-vul and Zun-kholbo. The NAP1 strain contains "non-photosynthetic" erythroxanthin sulfate, which is bound neither to the reaction center nor to the light-harvesting complex. Bacteriorubixanthinal, zeaxanthin and erythroxanthin are the main photosynthetic carotenoids of NAP1, coupled to the light- harvesting system. This system is composed of inner LH1 complex and reaction center, with no peripheral LH2 complexes. The photosynthetic unit size, in comparison with a typical anaerobic phototroph Rhodobacter sphaeroides, is limited due to the absence of LH2 antenna. The purified LH1-RC complex isolated from NAP1 is relatively thermostable,...
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