Hugueney P, Badillo A, Chen H C, Klein A, Hirschberg J, Camara B, Kuntz M
Institut de Biologie Moléculaire des Plantes du CNRS, Strasbourg, France.
Plant J. 1995 Sep;8(3):417-24. doi: 10.1046/j.1365-313x.1995.08030417.x.
The biosynthetic pathway of cyclic carotenoid is known to be quantitatively and qualitatively different in the non-green plastids of Capsicum annuum fruits compared with chloroplasts. Here, the cloning is described of a novel cDNA from this organism, which encodes an enzyme catalyzing the cyclization of lycopene to beta-carotene when expressed in Escherichia coli. The corresponding gene is constitutively expressed during fruit development. Significant amino acid sequence identity was observed between this enzyme and capsanthin/capsorubin synthase which is involved in the synthesis of the species-specific red carotenoids of C. annuum fruits. The latter enzyme was found also to possess a lycopene beta-cyclase activity when expressed in E. coli. A model is proposed for the origin of the capsanthin/capsorubin synthase gene and the role of this enzyme, together with the newly cloned lycopene cyclase, in the specific re-channeling of linear carotenoids into beta-cyclic carotenoids in C. annuum ripening fruits.
与叶绿体相比，辣椒果实非绿色质体中类胡萝卜素的生物合成途径在数量和质量上都有所不同。本文描述了从该生物体中克隆出的一个新的cDNA，该cDNA编码的一种酶在大肠杆菌中表达时能催化番茄红素环化生成β-胡萝卜素。相应的基因在果实发育过程中持续表达。该酶与辣椒红素/辣椒玉红素合酶之间存在显著的氨基酸序列同一性，后者参与辣椒果实中物种特异性红色类胡萝卜素的合成。当在大肠杆菌中表达时，还发现后者酶具有番茄红素β-环化酶活性。本文提出了一个关于辣椒红素/辣椒玉红素合酶基因起源的模型，以及该酶与新克隆的番茄红素环化酶在辣椒成熟果实中将线性类胡萝卜素特异性重新导向β-环化类胡萝卜素过程中的作用。
