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Retinal–Carotenoid Interactions in a Sodium-Ion-Pumping Rhodopsin: Implications on Oligomerization and Thermal Stability
[Image: see text] Microbial rhodopsin (also called retinal protein)–carotenoid conjugates represent a unique class of light-harvesting (LH) complexes, but their specific interactions and LH properties are not completely elucidated as only few rhodopsins are known to bind carotenoids. Here, we report...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2023
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10026069/ https://www.ncbi.nlm.nih.gov/pubmed/36857147 http://dx.doi.org/10.1021/acs.jpcb.2c07502 |
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author | Ghosh, Mihir Misra, Ramprasad Bhattacharya, Sudeshna Majhi, Koushik Jung, Kwang-Hwan Sheves, Mordechai |
author_facet | Ghosh, Mihir Misra, Ramprasad Bhattacharya, Sudeshna Majhi, Koushik Jung, Kwang-Hwan Sheves, Mordechai |
author_sort | Ghosh, Mihir |
collection | PubMed |
description | [Image: see text] Microbial rhodopsin (also called retinal protein)–carotenoid conjugates represent a unique class of light-harvesting (LH) complexes, but their specific interactions and LH properties are not completely elucidated as only few rhodopsins are known to bind carotenoids. Here, we report a natural sodium-ion (Na(+))-pumping Nonlabens (Donghaeana) dokdonensis rhodopsin (DDR2) binding with a carotenoid salinixanthin (Sal) to form a thermally stable rhodopsin–carotenoid complex. Different spectroscopic studies were employed to monitor the retinal–carotenoid interaction as well as the thermal stability of the protein, while size-exclusion chromatography (SEC) and homology modeling are performed to understand the protein oligomerization process. In analogy with that of another Na(+)-pumping protein Krokinobacter eikastus rhodopsin 2 (KR2), we propose that DDR2 (studied concentration range: 2 × 10(–6) to 4 × 10(–5) M) remains mainly as a pentamer at room temperature and neutral pH, while heating above 55 °C partially converted it into a thermally less stable oligomeric form of the protein. This process is affected by both the pH and concentration. At high concentrations (4 × 10(–5) to 2 × 10(–4) M), the protein adopts a pentamer form reflected in the excitonic circular dichroism (CD) spectrum. In the presence of Sal, the thermal stability of DDR2 is increased significantly, and the pigment is stable even at 85 °C. The results presented could have implications in designing stable rhodopsin–carotenoid antenna complexes. |
format | Online Article Text |
id | pubmed-10026069 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-100260692023-03-21 Retinal–Carotenoid Interactions in a Sodium-Ion-Pumping Rhodopsin: Implications on Oligomerization and Thermal Stability Ghosh, Mihir Misra, Ramprasad Bhattacharya, Sudeshna Majhi, Koushik Jung, Kwang-Hwan Sheves, Mordechai J Phys Chem B [Image: see text] Microbial rhodopsin (also called retinal protein)–carotenoid conjugates represent a unique class of light-harvesting (LH) complexes, but their specific interactions and LH properties are not completely elucidated as only few rhodopsins are known to bind carotenoids. Here, we report a natural sodium-ion (Na(+))-pumping Nonlabens (Donghaeana) dokdonensis rhodopsin (DDR2) binding with a carotenoid salinixanthin (Sal) to form a thermally stable rhodopsin–carotenoid complex. Different spectroscopic studies were employed to monitor the retinal–carotenoid interaction as well as the thermal stability of the protein, while size-exclusion chromatography (SEC) and homology modeling are performed to understand the protein oligomerization process. In analogy with that of another Na(+)-pumping protein Krokinobacter eikastus rhodopsin 2 (KR2), we propose that DDR2 (studied concentration range: 2 × 10(–6) to 4 × 10(–5) M) remains mainly as a pentamer at room temperature and neutral pH, while heating above 55 °C partially converted it into a thermally less stable oligomeric form of the protein. This process is affected by both the pH and concentration. At high concentrations (4 × 10(–5) to 2 × 10(–4) M), the protein adopts a pentamer form reflected in the excitonic circular dichroism (CD) spectrum. In the presence of Sal, the thermal stability of DDR2 is increased significantly, and the pigment is stable even at 85 °C. The results presented could have implications in designing stable rhodopsin–carotenoid antenna complexes. American Chemical Society 2023-03-01 /pmc/articles/PMC10026069/ /pubmed/36857147 http://dx.doi.org/10.1021/acs.jpcb.2c07502 Text en © 2023 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Ghosh, Mihir Misra, Ramprasad Bhattacharya, Sudeshna Majhi, Koushik Jung, Kwang-Hwan Sheves, Mordechai Retinal–Carotenoid Interactions in a Sodium-Ion-Pumping Rhodopsin: Implications on Oligomerization and Thermal Stability |
title | Retinal–Carotenoid
Interactions in a Sodium-Ion-Pumping
Rhodopsin: Implications on Oligomerization and Thermal Stability |
title_full | Retinal–Carotenoid
Interactions in a Sodium-Ion-Pumping
Rhodopsin: Implications on Oligomerization and Thermal Stability |
title_fullStr | Retinal–Carotenoid
Interactions in a Sodium-Ion-Pumping
Rhodopsin: Implications on Oligomerization and Thermal Stability |
title_full_unstemmed | Retinal–Carotenoid
Interactions in a Sodium-Ion-Pumping
Rhodopsin: Implications on Oligomerization and Thermal Stability |
title_short | Retinal–Carotenoid
Interactions in a Sodium-Ion-Pumping
Rhodopsin: Implications on Oligomerization and Thermal Stability |
title_sort | retinal–carotenoid
interactions in a sodium-ion-pumping
rhodopsin: implications on oligomerization and thermal stability |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10026069/ https://www.ncbi.nlm.nih.gov/pubmed/36857147 http://dx.doi.org/10.1021/acs.jpcb.2c07502 |
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