Cargando…

Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae

Photosynthetic organisms use pigment–protein complexes to capture the sunlight that powers most life on earth. Within these complexes, the position of the embedded pigments is all optimized for light harvesting. At the same time, the protein scaffold undergoes thermal fluctuations that vary the stru...

Descripción completa

Detalles Bibliográficos
Autores principales: Moya, Raymundo, Norris, Audrey C., Spangler, Leah C., Scholes, Gregory D., Schlau-Cohen, Gabriela S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: AIP Publishing LLC 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9894659/
https://www.ncbi.nlm.nih.gov/pubmed/35868944
http://dx.doi.org/10.1063/5.0095763
_version_ 1784881785713197056
author Moya, Raymundo
Norris, Audrey C.
Spangler, Leah C.
Scholes, Gregory D.
Schlau-Cohen, Gabriela S.
author_facet Moya, Raymundo
Norris, Audrey C.
Spangler, Leah C.
Scholes, Gregory D.
Schlau-Cohen, Gabriela S.
author_sort Moya, Raymundo
collection PubMed
description Photosynthetic organisms use pigment–protein complexes to capture the sunlight that powers most life on earth. Within these complexes, the position of the embedded pigments is all optimized for light harvesting. At the same time, the protein scaffold undergoes thermal fluctuations that vary the structure, and, thus, photophysics, of the complexes. While these variations are averaged out in ensemble measurements, single-molecule spectroscopy provides the ability to probe these conformational changes. We used single-molecule fluorescence spectroscopy to identify the photophysical substates reflective of distinct conformations and the associated conformational dynamics in phycoerythrin 545 (PE545), a pigment–protein complex from cryptophyte algae. Rapid switching between photophysical states was observed, indicating that ensemble measurements average over a conformational equilibrium. A highly quenched conformation was also identified, and its population increased under high light. This discovery establishes that PE545 has the characteristics to serve as a photoprotective site. Finally, unlike homologous proteins from the evolutionarily related cyanobacteria and red algae, quenching was not observed upon photobleaching, which may allow for robust photophysics without the need for rapid repair or replacement machinery. Collectively, these observations establish the presence of a rich and robust set of conformational states of PE545. Cryptophytes exhibit particularly diverse energetics owing to the variety of microenvironments in which they survive, and the conformational states and dynamics reported here may provide photophysical flexibility that contributes to their remarkable ability to flourish under diverse conditions.
format Online
Article
Text
id pubmed-9894659
institution National Center for Biotechnology Information
language English
publishDate 2022
publisher AIP Publishing LLC
record_format MEDLINE/PubMed
spelling pubmed-98946592023-02-03 Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae Moya, Raymundo Norris, Audrey C. Spangler, Leah C. Scholes, Gregory D. Schlau-Cohen, Gabriela S. J Chem Phys ARTICLES Photosynthetic organisms use pigment–protein complexes to capture the sunlight that powers most life on earth. Within these complexes, the position of the embedded pigments is all optimized for light harvesting. At the same time, the protein scaffold undergoes thermal fluctuations that vary the structure, and, thus, photophysics, of the complexes. While these variations are averaged out in ensemble measurements, single-molecule spectroscopy provides the ability to probe these conformational changes. We used single-molecule fluorescence spectroscopy to identify the photophysical substates reflective of distinct conformations and the associated conformational dynamics in phycoerythrin 545 (PE545), a pigment–protein complex from cryptophyte algae. Rapid switching between photophysical states was observed, indicating that ensemble measurements average over a conformational equilibrium. A highly quenched conformation was also identified, and its population increased under high light. This discovery establishes that PE545 has the characteristics to serve as a photoprotective site. Finally, unlike homologous proteins from the evolutionarily related cyanobacteria and red algae, quenching was not observed upon photobleaching, which may allow for robust photophysics without the need for rapid repair or replacement machinery. Collectively, these observations establish the presence of a rich and robust set of conformational states of PE545. Cryptophytes exhibit particularly diverse energetics owing to the variety of microenvironments in which they survive, and the conformational states and dynamics reported here may provide photophysical flexibility that contributes to their remarkable ability to flourish under diverse conditions. AIP Publishing LLC 2022-07-21 2022-07-19 /pmc/articles/PMC9894659/ /pubmed/35868944 http://dx.doi.org/10.1063/5.0095763 Text en © 2022 Author(s). https://creativecommons.org/licenses/by/4.0/All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ). Published open access through an agreement with Massachusetts Institute of Technology 2167
spellingShingle ARTICLES
Moya, Raymundo
Norris, Audrey C.
Spangler, Leah C.
Scholes, Gregory D.
Schlau-Cohen, Gabriela S.
Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
title Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
title_full Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
title_fullStr Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
title_full_unstemmed Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
title_short Observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
title_sort observation of conformational dynamics in single light-harvesting proteins from cryptophyte algae
topic ARTICLES
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9894659/
https://www.ncbi.nlm.nih.gov/pubmed/35868944
http://dx.doi.org/10.1063/5.0095763
work_keys_str_mv AT moyaraymundo observationofconformationaldynamicsinsinglelightharvestingproteinsfromcryptophytealgae
AT norrisaudreyc observationofconformationaldynamicsinsinglelightharvestingproteinsfromcryptophytealgae
AT spanglerleahc observationofconformationaldynamicsinsinglelightharvestingproteinsfromcryptophytealgae
AT scholesgregoryd observationofconformationaldynamicsinsinglelightharvestingproteinsfromcryptophytealgae
AT schlaucohengabrielas observationofconformationaldynamicsinsinglelightharvestingproteinsfromcryptophytealgae