The Calvin cycle in cyanobacteria is regulated by CP12 via the NAD(H)/NADP(H) ratio under light/dark conditions
The Calvin cycle in cyanobacteria is regulated by CP12 via the NAD(H)/NADP(H) ratio under light/dark conditions
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DOI：
10.1111/j.1365-313x.2005.02391.x
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发表时间：
2005-05-01
期刊：
影响因子：
7.2
通讯作者：
Shigeoka, S
中科院分区：
文献类型：
--
作者：
Tamoi, M;Miyazaki, T;Shigeoka, S
在黑暗中生长的聚球藻PCC 7942细胞中，NAD（H）和NADP（H）的浓度分别为128 +/- 2.5和483 +/- 4.0 μ m m，而在光照条件下的细胞中，NAD（H）和NADP（H）的浓度分别为100 +/- 5.0和649 +/- 7.0 μ m。凝胶过滤的分析表明，在光/暗条件下蓝藻细胞中NADP（H）与NAD（H）的比率的变化控制着由磷酸核酮糖激酶（phosphoribulokinase，PKK）、CP 12和甘油醛-3-磷酸脱氢酶（glyceraldehyde-3-phosphate dehydrogenase，GAPDH）组成的PKK/CP 12/GAPDH复合物（约520 kDa）的可逆解离。S. 7942 CP 12缺少形成高等植物CP 12 N-末端肽环所必需的两个Cys残基，但S. 7942 CP 12具有与PRK相关的能力。在连续光照条件下，其中CP 12基因被卡那霉素抗性盒基因破坏的突变细胞的生长几乎与野生型细胞的生长相同。然而，在光/暗循环（12 h/12 h）下，与野生型细胞相比，CP 12破坏的突变体细胞的生长受到显著抑制。在黑暗中，与野生型细胞相比，突变体细胞显示出O-2消耗率降低和核酮糖1，5-二磷酸水平增加。这些数据表明，在光照和黑暗条件下，CP 12与β-氨基丁酸和GAPDH的寡聚化调节两种酶的活性，从而调节从卡尔文循环到氧化戊糖磷酸循环的碳流。
In Synechococcus PCC7942 cells grown in the dark, the concentrations of NAD(H) and NADP(H) were 128 +/- 2.5 and 483 +/- 4.0 mu m, respectively, while those in the cells under light conditions were 100 +/- 5.0 and 649 +/- 7.0 mu m, respectively. Analysis of gel filtration indicated that the change of the ratio of NADP(H) to NAD(H) in cyanobacterial cells under light/dark conditions controls the reversible dissociation of the PRK/CP12/GAPDH complex (approximately 520 kDa) consisting of phosphoribulokinase (PRK), CP12, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). S. 7942 CP12 lacked the two Cys residues essential for formation of the N-terminal peptide loop in the CP12 of higher plants, but the N-terminal region of S. 7942 CP12 had the ability to be associated with PRK. The growth of mutant cells in which the CP12 gene was disrupted by a kanamycin resistance cartridge gene was almost the same as that of wild-type cells under continuous light conditions. However, under the light/dark cycle (12 h/12 h), the growth of CP12-disrupted mutant cells was significantly inhibited compared with that of wild-type cells. The mutant cells showed a decreased rate of O-2 consumption and an increased level of ribulose 1,5-bisphosphate compared with wild-type cells in the dark. These data suggest that under light and dark conditions, the oligomerization of CP12 with PRK and GAPDH regulates the activities of both enzymes and thus the carbon flow from the Calvin cycle to the oxidative pentose phosphate cycle.