RcaE is a complementary chromatic adaptation photoreceptor required for green and red light responsiveness
RcaE is a complementary chromatic adaptation photoreceptor required for green and red light responsiveness
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DOI：
10.1046/j.1365-2958.2003.03853.x
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发表时间：
2004-01-01
影响因子：
3.6
通讯作者：
Kehoe, DM
中科院分区：
文献类型：
--
作者：
Terauchi, K;Montgomery, BL;Kehoe, DM
近年来在光合作用和非光合作用的原核生物中发现了大量光敏色素光受体基因，这使得人们努力了解它们在环境适应中的生理作用。该类中的一种受体RcaE参与控制互补色适应，这一过程调节蓝藻中编码光收集蛋白的操纵子的转录。虽然所有先前确定的光敏色素反应对红光和远红光最敏感，但互补色适应的独特之处在于它对绿光和红光都有响应。在这里，我们提出了生化和遗传证据，证明RcaE是一种光感受器，它需要198位的半胱氨酸以类似于植物光敏色素中发色团附着的方式共价连接开链四吡啶。此外，尽管野生型rcaE基因可以挽救rcaE零突变体的红光和绿光响应，但一个将半胱氨酸198密码子转化为丙氨酸密码子的基因挽救了红光而不是绿光响应。因此，RcaE是互补色适应过程中绿光和红光响应所必需的光感受器，是第一个被发现的光敏色素类传感器，它参与感知和响应绿光和红光，而不是红光和远红光。
The recent discovery of large numbers of phytochrome photoreceptor genes in both photosynthetic and non-photosynthetic prokaryotes has led to efforts to understand their physiological roles in environmental acclimation. One receptor in this class, RcaE, is involved in controlling complementary chromatic adaptation, a process that regulates the transcription of operons encoding light-harvesting proteins in cyanobacteria. Although all previously identified phytochrome responses are maximally sensitive to red and far red light, complementary chromatic adaptation is unique in that it is responsive to green and red light. Here, we present biochemical and genetic evidence demonstrating that RcaE is a photoreceptor and that it requires the cysteine at position 198 to ligate an open chain tetrapyrrole covalently in a manner analogous to chromophore attachment in plant phytochromes. Furthermore, although the wild-type rcaE gene can rescue red and green light photoresponses of an rcaE null mutant, a gene in which the codon for cysteine 198 is converted to an alanine codon rescues the red light but not the green light response. Thus, RcaE is a photoreceptor that is required for both green and red light responsiveness during complementary chromatic adaptation and is the first identified phytochrome class sensor that is involved in sensing and responding to green and red light rather than red and far red light.