Turner L, Houghton J D, Brown S B
Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Planta. 1997;201(1):78-83. doi: 10.1007/BF01258683.
Much controversy exists as to the level at which light exerts control over the biosynthesis of the photosynthetic apparatus in higher plants and other organisms. The eukaryotic red alga Cyanidium caldarium, like higher plants, undergoes light induction of chlorophyll synthesis. In addition to chlorophyll a the alga also synthesises the linear tetrapyrrole phycocyanobilin, which is combined with alpha or beta apobiliproteins to form phycocyanin, the major light-harvesting pigment in this organism. We have previously shown that the tetrapyrrole precursor 5-aminolaevulinic acid (ALA) can substitute for light in inducing the biosynthesis of the phycocyanobilin moiety of this protein. We have also described the appearance of a protein of similar isoelectric point and molecular weight to phycocyanin in ALA-fed cells (Turner et al., 1992, Plant Physiol Biochem 30: 309-314). We now report on the protein's immunological and sequence identity with phycocyanin alpha and beta subunits, and provide further evidence that bilin-apoprotein ligation is light dependent.
关于光在何种水平上控制高等植物和其他生物体中光合机构的生物合成，存在诸多争议。真核红藻嗜热栖热放线菌（Cyanidium caldarium）与高等植物一样，会经历叶绿素合成的光诱导过程。除了叶绿素a，该藻类还合成线性四吡咯藻蓝胆素，它与α或β脱辅基脂蛋白结合形成藻蓝蛋白，这是该生物体中的主要捕光色素。我们之前已经表明，四吡咯前体5-氨基乙酰丙酸（ALA）可以替代光来诱导该蛋白藻蓝胆素部分的生物合成。我们还描述了在喂食ALA的细胞中出现了一种与藻蓝蛋白等电点和分子量相似的蛋白质（Turner等人，1992年，《植物生理学与生物化学》30：309 - 314）。我们现在报告该蛋白质与藻蓝蛋白α和β亚基的免疫学和序列同一性，并提供进一步证据表明胆素 - 脱辅基脂蛋白连接是光依赖性的。
