Trophic Mode-Dependent Proteomic Analysis Reveals Functional Significance of Light-Independent Chlorophyll Synthesis in Synechocystis sp PCC 6803
Trophic Mode-Dependent Proteomic Analysis Reveals Functional Significance of Light-Independent Chlorophyll Synthesis in Synechocystis sp PCC 6803
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DOI：
10.1016/j.molp.2016.08.006
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发表时间：
2017-01-09
期刊：
影响因子：
27.5
通讯作者：
Wang, Yingchun
中科院分区：
文献类型：
--
作者：
Fang, Longfa;Ge, Haitao;Wang, Yingchun
光合模式生物集胞藻属 sp。 PCC 6803 可以以不同的营养模式生长，具体取决于光和外源有机碳源的可用性。然而，蛋白质谱如何变化以促进细胞以不同模式差异增殖尚未得到全面研究。使用基于同量异序标记的定量蛋白质组学，我们同时鉴定并量化了四种不同营养模式（即自养、异养、光异养和混合营养模式）的 45% 集胞藻蛋白质组。在四种营养模式下差异表达的 155 种蛋白质中，参与氮同化和不依赖光的叶绿素合成的蛋白质在混合营养模式下显着上调，同时感知碳和氮同化状态的 P-II 磷酸化显着增加。此外，使用不依赖于光的叶绿素合成中存在缺陷的突变体进行的功能研究表明，该途径对于循环光/暗照明条件下的叶绿素积累很重要，这种条件模仿了某些自然栖息地的昼夜循环。总的来说，这些结果提供了蓝藻中营养模式依赖性蛋白质表达的最全面的信息，并揭示了营养生长中不依赖于光的叶绿素合成的功能意义。
The photosynthetic model organism Synechocystis sp. PCC 6803 can grow in different trophic modes, depending on the availability of light and exogenous organic carbon source. However, how the protein profile changes to facilitate the cells differentially propagate in different modes has not been comprehensively investigated. Using isobaric labeling-based quantitative proteomics, we simultaneously identified and quantified 45% Synechocystis proteome across four different trophic modes, i.e., autotrophic, heterotrophic, photoheterotrophic, and mixotrophic modes. Among the 155 proteins that are differentially expressed across four trophic modes, proteins involved in nitrogen assimilation and light-independent chlorophyll synthesis are dramatically upregulated in the mixotrophic mode, concomitant with a dramatic increase of P-II phosphorylation that senses carbon and nitrogen assimilation status. Moreover, functional study using a mutant defective in light-independent chlorophyll synthesis revealed that this pathway is important for chlorophyll accumulation under a cycled light/dark illumination regime, a condition mimicking day/night cycles in certain natural habitats. Collectively, these results provide the most comprehensive information on trophic mode-dependent protein expression in cyanobacterium, and reveal the functional significance of light-independent chlorophyll synthesis in trophic growth.