Cargando…
Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning
The genomes of some purple photosynthetic bacteria contain a multigene puc family encoding a series of α- and β-polypeptides that together form a heterogeneous antenna of light-harvesting 2 (LH2) complexes. To unravel this complexity, we generated four sets of puc deletion mutants in Rhodopseudomona...
Autores principales: | , , , , , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
National Academy of Sciences
2022
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9618040/ https://www.ncbi.nlm.nih.gov/pubmed/36251992 http://dx.doi.org/10.1073/pnas.2210109119 |
_version_ | 1784820966041321472 |
---|---|
author | Qian, Pu Nguyen-Phan, Cam T. Gardiner, Alastair T. Croll, Tristan I. Roszak, Aleksander W. Southall, June Jackson, Philip J. Vasilev, Cvetelin Castro-Hartmann, Pablo Sader, Kasim Hunter, C. Neil Cogdell, Richard J. |
author_facet | Qian, Pu Nguyen-Phan, Cam T. Gardiner, Alastair T. Croll, Tristan I. Roszak, Aleksander W. Southall, June Jackson, Philip J. Vasilev, Cvetelin Castro-Hartmann, Pablo Sader, Kasim Hunter, C. Neil Cogdell, Richard J. |
author_sort | Qian, Pu |
collection | PubMed |
description | The genomes of some purple photosynthetic bacteria contain a multigene puc family encoding a series of α- and β-polypeptides that together form a heterogeneous antenna of light-harvesting 2 (LH2) complexes. To unravel this complexity, we generated four sets of puc deletion mutants in Rhodopseudomonas palustris, each encoding a single type of pucBA gene pair and enabling the purification of complexes designated as PucA-LH2, PucB-LH2, PucD-LH2, and PucE-LH2. The structures of all four purified LH2 complexes were determined by cryogenic electron microscopy (cryo-EM) at resolutions ranging from 2.7 to 3.6 Å. Uniquely, each of these complexes contains a hitherto unknown polypeptide, γ, that forms an extended undulating ribbon that lies in the plane of the membrane and that encloses six of the nine LH2 αβ-subunits. The γ-subunit, which is located near to the cytoplasmic side of the complex, breaks the C9 symmetry of the LH2 complex and binds six extra bacteriochlorophylls (BChls) that enhance the 800-nm absorption of each complex. The structures show that all four complexes have two complete rings of BChls, conferring absorption bands centered at 800 and 850 nm on the PucA-LH2, PucB-LH2, and PucE-LH2 complexes, but, unusually, the PucD-LH2 antenna has only a single strong near-infared (NIR) absorption peak at 803 nm. Comparison of the cryo-EM structures of these LH2 complexes reveals altered patterns of hydrogen bonds between LH2 αβ-side chains and the bacteriochlorin rings, further emphasizing the major role that H bonds play in spectral tuning of bacterial antenna complexes. |
format | Online Article Text |
id | pubmed-9618040 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | National Academy of Sciences |
record_format | MEDLINE/PubMed |
spelling | pubmed-96180402022-10-31 Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning Qian, Pu Nguyen-Phan, Cam T. Gardiner, Alastair T. Croll, Tristan I. Roszak, Aleksander W. Southall, June Jackson, Philip J. Vasilev, Cvetelin Castro-Hartmann, Pablo Sader, Kasim Hunter, C. Neil Cogdell, Richard J. Proc Natl Acad Sci U S A Biological Sciences The genomes of some purple photosynthetic bacteria contain a multigene puc family encoding a series of α- and β-polypeptides that together form a heterogeneous antenna of light-harvesting 2 (LH2) complexes. To unravel this complexity, we generated four sets of puc deletion mutants in Rhodopseudomonas palustris, each encoding a single type of pucBA gene pair and enabling the purification of complexes designated as PucA-LH2, PucB-LH2, PucD-LH2, and PucE-LH2. The structures of all four purified LH2 complexes were determined by cryogenic electron microscopy (cryo-EM) at resolutions ranging from 2.7 to 3.6 Å. Uniquely, each of these complexes contains a hitherto unknown polypeptide, γ, that forms an extended undulating ribbon that lies in the plane of the membrane and that encloses six of the nine LH2 αβ-subunits. The γ-subunit, which is located near to the cytoplasmic side of the complex, breaks the C9 symmetry of the LH2 complex and binds six extra bacteriochlorophylls (BChls) that enhance the 800-nm absorption of each complex. The structures show that all four complexes have two complete rings of BChls, conferring absorption bands centered at 800 and 850 nm on the PucA-LH2, PucB-LH2, and PucE-LH2 complexes, but, unusually, the PucD-LH2 antenna has only a single strong near-infared (NIR) absorption peak at 803 nm. Comparison of the cryo-EM structures of these LH2 complexes reveals altered patterns of hydrogen bonds between LH2 αβ-side chains and the bacteriochlorin rings, further emphasizing the major role that H bonds play in spectral tuning of bacterial antenna complexes. National Academy of Sciences 2022-10-17 2022-10-25 /pmc/articles/PMC9618040/ /pubmed/36251992 http://dx.doi.org/10.1073/pnas.2210109119 Text en Copyright © 2022 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by/4.0/This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY) (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Biological Sciences Qian, Pu Nguyen-Phan, Cam T. Gardiner, Alastair T. Croll, Tristan I. Roszak, Aleksander W. Southall, June Jackson, Philip J. Vasilev, Cvetelin Castro-Hartmann, Pablo Sader, Kasim Hunter, C. Neil Cogdell, Richard J. Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
title | Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
title_full | Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
title_fullStr | Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
title_full_unstemmed | Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
title_short | Cryo-EM structures of light-harvesting 2 complexes from Rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
title_sort | cryo-em structures of light-harvesting 2 complexes from rhodopseudomonas palustris reveal the molecular origin of absorption tuning |
topic | Biological Sciences |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9618040/ https://www.ncbi.nlm.nih.gov/pubmed/36251992 http://dx.doi.org/10.1073/pnas.2210109119 |
work_keys_str_mv | AT qianpu cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT nguyenphancamt cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT gardineralastairt cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT crolltristani cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT roszakaleksanderw cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT southalljune cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT jacksonphilipj cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT vasilevcvetelin cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT castrohartmannpablo cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT saderkasim cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT huntercneil cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning AT cogdellrichardj cryoemstructuresoflightharvesting2complexesfromrhodopseudomonaspalustrisrevealthemolecularoriginofabsorptiontuning |