Characterization of the Synechocystis PCC 6803 Fluorescence Recovery Protein involved in photoprotection
Characterization of the Synechocystis PCC 6803 Fluorescence Recovery Protein involved in photoprotection
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DOI：
10.1016/j.bbabio.2012.11.001
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发表时间：
2013-03-01
影响因子：
4.3
通讯作者：
Kirilovsky, Diana
中科院分区：
文献类型：
--
作者：
Gwizdala, Michal;Wilson, Adjele;Kirilovsky, Diana
在高辐照度下，大多数蓝细菌会诱导光保护机制，减少到达光合反应中心的能量，以避免形成危险的氧物种。这种机制迅速增加了蓝藻天线（藻胆体）水平多余能量的散热，是由橙色类胡萝卜素蛋白（OCP）的光活化触发的。在弱光条件下，荧光恢复蛋白 (FRP) 通过加速 OCP 的失活来介导全部天线容量的恢复。构建了几种 FRP 集胞藻突变体，并根据 OCP 相关光保护机制进行了表征。我们的结果表明，集胞藻 FRP 从 Met26 开始，而不是像之前建议的那样从 Met1（根据 Cyanobase 中的符号）开始。此外，编码 Met26 的 ATG 上游基因组区域的变化影响细胞中 OCP 的浓度。当 frp 基因处于 psbA2 启动子的控制之下时，长 FRP（从 Met1 开始）会在集胞藻细胞中合成，但其活性低于较短的蛋白质。集胞藻中短 frp 基因的过度表达使得短 FRP 能够从可溶性部分中分离出来。然而，该突变体中高浓度的 FRP 通过降低活化 OCP 的浓度来抑制光保护机制的诱导。因此，光保护的幅度不仅取决于OCP浓度，还取决于FRP的浓度。 FRP 和 OCP 的合成必须严格控制，以保持较低的 FRP 与 OCP 比率，以实现有效的光保护。 (C) 2012 Elsevier B.V. 保留所有权利。
Under high irradiance, most cyanobacteria induce a photoprotective mechanism that decreases the energy arriving at the photosynthetic reaction centers to avoid the formation of dangerous species of oxygen. This mechanism which rapidly increases the heat dissipation of excess energy at the level of the cyanobacterial antenna, the phycobilisomes, is triggered by the photoactivation of the Orange Carotenoid Protein (OCP). Under low light conditions, the Fluorescence Recovery Protein (FRP) mediates the recovery of the full antenna capacity by accelerating the deactivation of the OCP. Several FRP Synechocystis mutants were constructed and characterized in terms of the OCP-related photoprotective mechanism. Our results demonstrate that Synechocystis FRP starts at Met26 and not at Met1 (according to notation in Cyanobase) as was previously suggested. Moreover, changes in the genomic region upstream the ATG encoding for Met26 influenced the concentration of OCP in cells. A long FRP (beginning at Met1) is synthesized in Synechocystis cells when the frp gene is under the control of the psbA2 promoter but it is less active than the shorter protein. Overexpression of the short frp gene in Synechocystis enabled short FRP isolation from the soluble fraction. However, the high concentration of FRP in this mutant inhibited the induction of the photoprotective mechanism by decreasing the concentration of the activated OCP. Therefore, the amplitude of photoprotection depends on not only OCP concentration but also on that of FRP. The synthesis of FRP and OCP must be strictly regulated to maintain a low FRP to OCP ratio to allow efficient photoprotection. (C) 2012 Elsevier B.V. All rights reserved.