A photoactive carotenoid protein acting as light intensity sensor

作者：Wilson Adjele; Punginelli Claire; Gall Andrew; Bonetti Cosimo; Alexandre Maxime; Routaboul Jean Marc; Kerfeld Cheryl A; van Grondelle Rienk; Robert Bruno; Kennis John T M; Kirilovsky Diana^*

来源：Proceedings of the National Academy of Sciences, 2008, 105(33): 12075-12080.

DOI：10.1073/pnas.0804636105

• cyanobacteria
• nonphotochemical quenching
• photoprotection
• phycobilisome

Intense sunlight is dangerous for photosynthetic organisms. Cyanobacteria, like plants, protect themselves from light-induced stress by dissipating excess absorbed energy as heat. Recently, it was discovered that a soluble orange carotenoid protein, the OCP, is essential for this photoprotective mechanism. Here we show that the OCP is also a member of the family of photoactive proteins; it is a unique example of a photoactive protein containing a carotenoid as the photoresponsive chromophore. Upon illumination with blue-green light, the OCP undergoes a reversible transformation from its dark stable orange form to a red "active" form. The red form is essential for the induction of the photoprotective mechanism. The illumination induces structural changes affecting both the carotenoid and the protein. Thus, the OCP is a photoactive protein that senses light intensity and triggers photoprotection.

• 出版日期2008-8-19
• 单位中国地震局