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Unique double concentric ring organization of light harvesting complexes in Gemmatimonas phototrophica
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SYSNO ASEP 0484727 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Unique double concentric ring organization of light harvesting complexes in Gemmatimonas phototrophica Author(s) Dachev, Marko (MBU-M) ORCID
Bína, David (BC-A) RID, ORCID
Sobotka, Roman (MBU-M) RID, ORCID
Moravcová, Lenka (MBU-M)
Gardian, Zdenko (BC-A) RID
Kaftan, David (MBU-M) ORCID, RID
Šlouf, V. (CZ)
Fuciman, M. (CZ)
Polívka, Tomáš (BC-A) RID, ORCID
Koblížek, Michal (MBU-M) RID, ORCIDArticle number e2003943 Source Title PLOS Biology. - : Public Library of Science - ISSN 1544-9173
Roč. 15, č. 12 (2017)Number of pages 16 s. Language eng - English Country US - United States Keywords BACTERIUM CHLOROFLEXUS-AURANTIACUS ; EXCITATION-ENERGY TRANSFER ; PURPLE BACTERIA Subject RIV EE - Microbiology, Virology OECD category Microbiology Subject RIV - cooperation Biology Centre (since 2006) - Biophysics R&D Projects GA15-00703S GA ČR - Czech Science Foundation (CSF) GBP501/12/G055 GA ČR - Czech Science Foundation (CSF) LO1416 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support MBU-M - RVO:61388971 ; BC-A - RVO:60077344 UT WOS 000418943900019 EID SCOPUS 85039903888 DOI https://doi.org/10.1371/journal.pbio.2003943 Annotation The majority of life on Earth depends directly or indirectly on the sun as a source of energy. The initial step of photosynthesis is facilitated by light-harvesting complexes, which capture and transfer light energy into the reaction centers (RCs). Here, we analyzed the organization of photosynthetic (PS) complexes in the bacterium G. phototrophica, which so far is the only phototrophic representative of the bacterial phylum Gemmatimonadetes. The isolated complex has a molecular weight of about 800 +/- 100 kDa, which is approximately 2 times larger than the core complex of Rhodospirillum rubrum. The complex contains 62.4 +/- 4.7 bacteriochlorophyll (BChl) a molecules absorbing in 2 distinct infrared absorption bands with maxima at 816 and 868 nm. Using femtosecond transient absorption spectroscopy, we determined the energy transfer time between these spectral bands as 2 ps. Single particle analyses of the purified complexes showed that they were circular structures with an outer diameter of approximately 18 nm and a thickness of 7 nm. Based on the obtained, we propose that the LH complexes in G. phototrophica form 2 concentric rings surrounding the type 2 RC. The inner ring (corresponding to the B868 absorption band) is composed of 15 subunits and is analogous to the inner light-harvesting complex 1 (LH1) in purple bacteria. The outer ring is composed of 15 more distant BChl dimers with no or slow energy transfer between them, resulting in the B816 absorption band. This completely unique and elegant organization offers good structural stability, as well as high efficiency of light harvesting. Our results reveal that while the PS apparatus of Gemmatimonadetes was acquired via horizontal gene transfer from purple bacteria, it later evolved along its own pathway, devising a new arrangement of its light harvesting complexes. Workplace Institute of Microbiology Contact Eliška Spurná, eliska.spurna@biomed.cas.cz, Tel.: 241 062 231 Year of Publishing 2018
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