6PQ1
Structure of the Fremyella diplosiphon OCP1
Summary for 6PQ1
| Entry DOI | 10.2210/pdb6pq1/pdb |
| Descriptor | Orange carotenoid-binding protein, beta,beta-carotene-4,4'-dione (3 entities in total) |
| Functional Keywords | photoprotection, carotenoid binding protein, photosynthesis |
| Biological source | Tolypothrix sp. PCC 7601 |
| Total number of polymer chains | 1 |
| Total formula weight | 37014.46 |
| Authors | Sutter, M.,Dominguez-Martin, M.A.,Bao, H.,Kerfeld, C.A. (deposition date: 2019-07-08, release date: 2020-05-20, Last modification date: 2023-10-11) |
| Primary citation | Kuznetsova, V.,Dominguez-Martin, M.A.,Bao, H.,Gupta, S.,Sutter, M.,Kloz, M.,Rebarz, M.,Precek, M.,Chen, Y.,Petzold, C.J.,Ralston, C.Y.,Kerfeld, C.A.,Polivka, T. Comparative ultrafast spectroscopy and structural analysis of OCP1 and OCP2 from Tolypothrix. Biochim Biophys Acta Bioenerg, 1861:148120-148120, 2020 Cited by PubMed Abstract: The orange carotenoid protein (OCP) is a structurally and functionally modular photoactive protein involved in cyanobacterial photoprotection. Recently, based on bioinformatic analysis and phylogenetic relationships, new families of OCP have been described, OCP2 and OCPx. The first characterization of the OCP2 showed both faster photoconversion and back-conversion, and lower fluorescence quenching of phycobilisomes relative to the well-characterized OCP1. Moreover, OCP2 is not regulated by the fluorescence recovery protein (FRP). In this work, we present a comprehensive study combining ultrafast spectroscopy and structural analysis to compare the photoactivation mechanisms of OCP1 and OCP2 from Tolypothrix PCC 7601. We show that despite significant differences in their functional characteristics, the spectroscopic properties of OCP1 and OCP2 are comparable. This indicates that the OCP functionality is not directly related to the spectroscopic properties of the bound carotenoid. In addition, the structural analysis by X-ray footprinting reveals that, overall, OCP1 and OCP2 have grossly the same photoactivation mechanism. However, the OCP2 is less reactive to radiolytic labeling, suggesting that the protein is less flexible than OCP1. This observation could explain fast photoconversion of OCP2. PubMed: 31734194DOI: 10.1016/j.bbabio.2019.148120 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.61 Å) |
Structure validation
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