Evaluation of the relationship between color-tuning of photosynthetic excitons and thermodynamic stability of light-harvesting chromoproteins
| Autor: | M. RÄTSEP, A. LEHTMETS, L. KANGUR, K. TIMPMANN, K. LEIGER, Z.-Y. WANG-OTOMO, A. FREIBERG |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Photosynthetica, Vol 61, Iss 3, Pp 308-317 (2023) |
| Druh dokumentu: | article |
| ISSN: | 0300-3604 1573-9058 |
| DOI: | 10.32615/ps.2023.022 |
| Popis: | Color-tuning is a critical survival mechanism for photosynthetic organisms. Calcium ions are believed to enhance both spectral tuning and thermostability in obligatory calcium-containing sulfur purple bacteria. This study examined the thermo- and piezo stability of the LH1-RC complexes from two calcium-containing sulfur purple bacteria notable for their extreme red-shifted spectra. The results generally show limited reversibility of both temperature and pressure effects related to the malleability of calcium-binding sites. While the pressure-induced decomposition product closely resembles the calcium-depleted form of the chromoproteins, the thermally induced products reveal monomeric B777 and dimeric B820 forms of bacteriochlorophyll a, similar to those seen in non-sulfur purple bacteria treated with detergent. The study further found nearly unison melting of the protein tertiary and secondary structures. Overall, our findings do not support a direct link between color adjustment and thermodynamic stability in light-harvesting chromoproteins. |
| Databáze: | Directory of Open Access Journals |
| Externí odkaz: |
|