6PQ1

Structure of the Fremyella diplosiphon OCP1

6PQ1 の概要

• エントリーDOI: 10.2210/pdb6pq1/pdb
• 分子名称: Orange carotenoid-binding protein, beta,beta-carotene-4,4'-dione (3 entities in total)
• 機能のキーワード: photoprotection, carotenoid binding protein, photosynthesis
• 由来する生物種: Tolypothrix sp. PCC 7601
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 37014.46

構造登録者

Sutter, M.,Dominguez-Martin, M.A.,Bao, H.,Kerfeld, C.A. (登録日: 2019-07-08, 公開日: 2020-05-20, 最終更新日: 2023-10-11)

主引用文献

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

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: 31734194
DOI: 10.1016/j.bbabio.2019.148120

実験手法

X-RAY DIFFRACTION (1.61 Å)