Glycerate-3-phosphate, produced by CO2 fixation in the Calvin cycle, is critical for the synthesis of the D1 protein of photosystem II.
Glycerate-3-phosphate, produced by CO2 fixation in the Calvin cycle, is critical for the synthesis of the D1 protein of photosystem II.
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DOI：
10.1016/j.bbabio.2006.02.002
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发表时间：
2006-03
期刊：
影响因子：
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通讯作者：
S. Takahashi;N. Murata
中科院分区：
文献类型：
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作者：
S. Takahashi;N. Murata
我们最近证实，在完整的莱茵衣藻细胞中，通过Calvin循环阻断CO2固定可以抑制光系统II(PSII)中蛋白质的合成，特别是在光损伤后PSII修复过程中D1蛋白的合成。在本研究中，我们利用从菠菜叶片中分离出的完整叶绿体来研究这一现象的机制。当外源乙醇醛抑制合成核酮糖-1，5-二磷酸的磷酸核酮酸激酶而抑制CO2固定时，D1蛋白的从头合成也受到抑制。然而，当Calvin循环中CO2固定的产物3-磷酸甘油(3-PGA)被外源供应时，乙醇醛的抑制作用被取消。CO2供应的减少也抑制了D1蛋白的合成，这种抑制作用也被外源3-PGA所消除。这些发现表明，CO2固定产生的3-PGA的供应对D1蛋白的合成是重要的。3-PGA可能接受来自NADPH的电子，并降低抑制蛋白质合成的活性氧物种的水平，如D1蛋白。
We demonstrated recently that, in intact cells of Chlamydomonas reinhardtii, interruption of CO2fixation via the Calvin cycle inhibits the synthesis of proteins in photosystem II (PSII), in particular, synthesis of the D1 protein, during the repair of PSII after photodamage. In the present study, we investigated the mechanism responsible for this phenomenon using intact chloroplasts isolated from spinach leaves. When CO2fixation was inhibited by exogenous glycolaldehyde, which inhibits the phosphoribulokinase that synthesizes ribulose-1,5-bisphosphate, the synthesis de novo of the D1 protein was inhibited. However, when glycerate-3-phosphate (3-PGA), which is a product of CO2fixation in the Calvin cycle, was supplied exogenously, the inhibitory effect of glycolaldehyde was abolished. A reduced supply of CO2also suppressed the synthesis of the D1 protein, and this inhibitory effect was also abolished by exogenous 3-PGA. These findings suggest that the supply of 3-PGA, generated by CO2fixation, is important for the synthesis of the D1 Protein. It is likely that 3-PGA accepts electrons from NADPH and decreases the level of reactive oxygen species, which inhibit the synthesis of proteins, such as the D1 protein.