Characterisation of the photosynthetic complexes from the marine gammaproteobacterium Congregibacter litoralis KT71

0572692 - MBÚ 2024 RIV NL eng J - Journal Article
Gardiner, Alastair T. - Mujakić, Izabela - Bína, David - Gardian, Zdenko - Kopejtka, Karel - Nupur, Nupur - Qian, P. - Koblížek, Michal
Characterisation of the photosynthetic complexes from the marine gammaproteobacterium Congregibacter litoralis KT71.
Biochimica Et Biophysica Acta-Bioenergetics. Roč. 1864, č. 2 (2023), č. článku 148946. ISSN 0005-2728. E-ISSN 1879-2650
R&D Projects: GA ČR(CZ) GX19-28778X; GA ČR(CZ) GA20-01159S
Institutional support: RVO:61388971 ; RVO:60077344
Keywords : aap * Congregibacter * Photoheterotrophy * Photosynthesis * Lightharvesting * Purple bacteria
OECD category: Microbiology; Microbiology (BC-A)
Impact factor: 4.3, year: 2022
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0005272822004169?via%3Dihub

Possibly the most abundant group of anoxygenic phototrophs are marine photoheterotrophic Gammaproteobac-teria belonging to the NOR5/OM60 clade. As little is known about their photosynthetic apparatus, the photo-synthetic complexes from the marine phototrophic bacterium Congregibacter litoralis KT71 were purified and spectroscopically characterised. The intra-cytoplasmic membranes contain a smaller amount of photosynthetic complexes when compared with anaerobic purple bacteria. Moreover, the intra-cytoplasmic membranes contain only a minimum amount of peripheral LH2 complexes. The complexes are populated by bacteriochlorophyll a, spirilloxanthin and two novel ketocarotenoids, with biophysical and biochemical properties similar to previously characterised complexes from purple bacteria. The organization of the RC-LH1 complex has been further char-acterised using cryo-electron microscopy. The overall organisation is similar to the complex from the gam-maproteobacterium Thermochromatium tepidum, with the type-II reaction centre surrounded by a slightly elliptical LH1 antenna ring composed of 16 alpha beta-subunits with no discernible gap or pore. The RC-LH1 and LH2 apoproteins are phylogenetically related to other halophilic species but LH2 also to some alphaproteobacterial species. It seems that the reduction of light-harvesting apparatus and acquisition of novel ketocarotenoids in Congregibacter litoralis KT71 represent specific adaptations for operating the anoxygenic photosynthesis under aerobic conditions at sea.
Permanent Link: https://hdl.handle.net/11104/0343301