Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Biochim Biophys Acta Mol Cell Biol Lipids. 2020 Nov;1865(11):158665. doi: 10.1016/j.bbalip.2020.158665. Epub 2020 Feb 12.
The carotenoids are terpenoid fat-soluble pigments produced by plants, algae, and several bacteria and fungi. They are ubiquitous components of animal diets. Carotenoid cleavage oxygenase (CCO) superfamily members are involved in carotenoid metabolism and are present in all kingdoms of life. Throughout the animal kingdom, carotenoid oxygenases are widely distributed and they are completely absent only in two unicellular organisms, Monosiga and Leishmania. Mammals have three paralogs 15,15'-β-carotene oxygenase (BCO1), 9',10'-β-carotene oxygenase (BCO2) and RPE65. The first two enzymes are classical carotenoid oxygenases: they cleave carbon‑carbon double bonds and incorporate two atoms of oxygen in the substrate at the site of cleavage. The third, RPE65, is an unusual family member, it is the retinoid isomerohydrolase in the visual cycle that converts all-trans-retinyl ester into 11-cis-retinol. Here we discuss evolutionary aspects of the carotenoid cleavage oxygenase superfamily and their enzymology to deduce what insight we can obtain from their evolutionary conservation.
类胡萝卜素是植物、藻类和几种细菌和真菌产生的萜类脂溶性色素。它们是动物饮食中无处不在的成分。类胡萝卜素裂解加氧酶（CCO）超家族成员参与类胡萝卜素代谢，存在于所有生命领域。在整个动物王国中，类胡萝卜素加氧酶广泛分布，只有两种单细胞生物——Monosiga 和 Leishmania 完全没有。哺乳动物有三个同源基因 15、15'-β-胡萝卜素氧合酶（BCO1）、9'、10'-β-胡萝卜素氧合酶（BCO2）和 RPE65。前两种酶是经典的类胡萝卜素加氧酶：它们在底物的断裂部位裂解碳-碳双键，并在底物中掺入两个氧原子。第三种，RPE65，是一个不寻常的家族成员，它是视觉循环中的视黄醛异构酶，将全反式视黄醇酯转化为 11-顺式视黄醇。在这里，我们讨论了类胡萝卜素裂解加氧酶超家族的进化方面及其酶学，以推断我们可以从它们的进化保守中获得什么启示。
