Institute of Plant Biology, Biological Research Centre of Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged, Hungary.
Prog Lipid Res. 2013 Oct;52(4):539-61. doi: 10.1016/j.plipres.2013.07.001. Epub 2013 Jul 26.
Carotenoids (CARs) are a group of pigments that perform several important physiological functions in all kingdoms of living organisms. CARs serve as protective agents, which are essential structural components of photosynthetic complexes and membranes, and they play an important role in the light harvesting mechanism of photosynthesizing plants and cyanobacteria. The protection against reactive oxygen species, realized by quenching of singlet oxygen and the excited states of photosensitizing molecules, as well as by the scavenging of free radicals, is one of the main biological functions of CARs. X-ray crystallographic localization of CARs revealed that they are present at functionally and structurally important sites of both the PSI and PSII reaction centers. Characterization of a CAR-less cyanobacterial mutant revealed that while the absence of CARs prevents the formation of PSII complexes, it does not abolish the assembly and function of PSI. CAR molecules assist in the formation of protein subunits of the photosynthetic complexes by gluing together their protein components. In addition to their aforementioned indispensable functions, CARs have a substantial role in the formation and maintenance of proper cellular architecture, and potentially also in the protection of the translational machinery under stress conditions.
类胡萝卜素（CARs）是一组在所有生物界的生物体中发挥多种重要生理功能的色素。CARs 作为保护剂，是光合作用复合物和膜的必需结构成分，在光合植物和蓝细菌的光捕获机制中起着重要作用。通过淬灭单线态氧和光敏分子的激发态，以及清除自由基来抵御活性氧，是 CARs 的主要生物学功能之一。X 射线晶体学定位 CARs 表明，它们存在于 PSI 和 PSII 反应中心的功能和结构重要部位。对无 CAR 蓝细菌突变体的特征描述表明，虽然 CARs 的缺失阻止了 PSII 复合物的形成，但它并没有废除 PSI 的组装和功能。CAR 分子通过将其蛋白质成分粘在一起，协助光合作用复合物的蛋白质亚基的形成。除了它们上述的不可或缺的功能外，CARs 在适当的细胞结构的形成和维持中起着重要作用，并且在应激条件下保护翻译机制方面也具有潜在作用。
