Chenchiliyan, M, Timpmann, K, Jalviste, E et al. (3 more authors) (2016) Dimerization of core complexes as an efficient strategy for energy trapping in Rhodobacter sphaeroides. Biochimica et Biophysica Acta - Bioenergetics, 1857 (6). pp. 634-642. ISSN 0006-3002
Abstract
In the purple phototrophic bacterium Rhodobacter sphaeroides, light harvesting LH2 complexes transfer absorbed solar energy to RC-LH1-PufX core complexes, which are mainly found in the dimeric state. Many other purple phototrophs have monomeric core complexes and the basis for requiring dimeric cores is not fully established, so we analysed strains of Rba. sphaeroides that contain either native dimeric core complexes or altered monomeric cores harbouring a deletion of the first 12 residues from the N-terminus of PufX, which retains the PufX polypeptide but removes the major determinant of core complex dimerization. Membranes were purified from strains with dimeric or monomeric cores, and with either high or low levels of the LH2 complex. Samples were interrogated with absorption, steady-state fluorescence, and picosecond time-resolved fluorescence kinetic spectroscopies to reveal their light-harvesting and energy trapping properties. We find that under saturating excitation light intensity the photosynthetic membranes containing LH2 and monomeric core complexes have fluorescence lifetimes nearly twice that of membranes with LH2 plus dimeric core complexes. This trend of increased lifetime is maintained with RCs in the open state as well, and for two different levels of LH2 content. Thus, energy trapping is more efficient when photosynthetic membranes of Rba sphaeroides consist of RC-LH1-PufX dimers and LH2 complexes.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016, Elsevier Ltd. This is an author produced version of a paper published in Biochimica et Biophysica Acta - Bioenergetics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Photosynthesis; Light harvesting; Photosynthetic excitons; LH1; LH2; RC |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Molecular & Nanoscale Physics |
Depositing User: | Symplectic Publications |
Date Deposited: | 24 Jun 2016 10:21 |
Last Modified: | 11 Apr 2017 17:14 |
Published Version: | http://dx.doi.org/10.1016/j.bbabio.2016.03.020 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.bbabio.2016.03.020 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:99741 |