Effects of Phosphorylation of β Subunits of Phycocyanins on State Transition in the Model Cyanobacterium Synechocystis sp PCC 6803
Effects of Phosphorylation of β Subunits of Phycocyanins on State Transition in the Model Cyanobacterium Synechocystis sp PCC 6803
复制标题
藻蓝蛋白 β 亚基磷酸化对模型蓝藻集胞藻 PCC 6803 状态转变的影响
DOI：
10.1093/pcp/pcv118
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发表时间：
2015-10-01
影响因子：
4.9
通讯作者：
Wang, Qiang
中科院分区：
文献类型：
--
作者：
Chen, Zhuo;Zhan, Jiao;Wang, Qiang
集胞藻属PCC 6803（Synechocystis sp. PCC 6803）是一种模式蓝藻，广泛用于光合作用和环境适应性的研究。虽然已经预测了几十种对Ser/Thr/Tyr残基具有特异性的蛋白激酶和磷酸酶，但在集胞藻中仅知道少数底物蛋白。在这项研究中，我们报告了194个体内磷酸化位点从149个蛋白质集胞藻，这是确定使用的组合肽预分馏，二氧化钛富集和液相色谱-串联质谱（LC-MS/MS）分析。这些磷酸化的蛋白质涉及多种生物过程，如光合作用。在所有鉴定的参与光合作用的磷蛋白中，发现藻蓝蛋白的β亚基（CpcBs）在Ser 22、Ser 49、Thr 94和Ser 154上被磷酸化。通过定点突变，构建了四个非磷酸化突变体。cpcB突变体的体内表征显示在高光辐照下生长较慢，并且显示荧光淬灭至较低水平，并且藻胆体（PBS）内的能量转移效率较低。值得注意的是，非磷酸化突变体表现出比野生型更慢的状态转变。这些结果表明，CpcBs的磷酸化状态影响着集胞藻光合作用的能量传递和状态转换。这项研究提供了新的见解蛋白磷酸化的分子机制，在蓝藻光合作用的调节，并可能有助于阐明整个调控网络连接激酶的生理底物。
Synechocystis sp. PCC 6803 (hereafter Synechocystis) is a model cyanobacterium and has been used extensively for studies concerned with photosynthesis and environmental adaptation. Although dozens of protein kinases and phosphatases with specificity for Ser/Thr/Tyr residues have been predicted, only a few substrate proteins are known in Synechocystis. In this study, we report 194 in vivo phosphorylation sites from 149 proteins in Synechocystis, which were identified using a combination of peptide pre-fractionation, TiO2 enrichment and liquid chromatograpy-tandem mass spectrometry (LC-MS/MS) analysis. These phosphorylated proteins are implicated in diverse biological processes, such as photosynthesis. Among all identified phosphoproteins involved in photosynthesis, the beta subunits of phycocyanins (CpcBs) were found to be phosphorylated on Ser22, Ser49, Thr94 and Ser154. Four non-phosphorylated mutants were constructed by using site-directed mutagenesis. The in vivo characterization of the cpcB mutants showed a slower growth under high light irradiance and displayed fluorescence quenching to a lower level and less efficient energy transfer inside the phycobilisome (PBS). Notably, the non-phosphorylated mutants exhibited a slower state transition than the wild type. The current results demonstrated that the phosphorylation status of CpcBs affects the energy transfer and state transition of photosynthesis in Synechocystis. This study provides novel insights into the molecular mechanisms of protein phosphorylation in the regulation of photosynthesis in cyanobacteria and may facilitate the elucidation of the entire regulatory network by linking kinases to their physiological substrates.