Wilson Adjélé, 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
Commissariat à l'Energie Atomique, Institut de Biologie et Technologies de Saclay, Centre National de la Recherche Scientifique, 91191 Gif sur Yvette, France.
Proc Natl Acad Sci U S A. 2008 Aug 19;105(33):12075-80. doi: 10.1073/pnas.0804636105. Epub 2008 Aug 7.
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.
强烈的阳光对光合生物来说是危险的。蓝细菌与植物一样，通过将多余的吸收能量以热量形式耗散来保护自身免受光诱导的胁迫。最近，人们发现一种可溶性橙色类胡萝卜素蛋白（OCP）对于这种光保护机制至关重要。在这里，我们表明OCP也是光活性蛋白家族的一员；它是一种独特的以类胡萝卜素作为光响应发色团的光活性蛋白。在用蓝绿光照射时，OCP会从其黑暗稳定的橙色形式发生可逆转变，成为红色的“活性”形式。红色形式对于光保护机制的诱导至关重要。光照会引起影响类胡萝卜素和蛋白质的结构变化。因此，OCP是一种能够感知光强度并触发光保护作用的光活性蛋白。
