Modulation of the major paths of carbon in photorespiratory mutants of synechocystis.
Modulation of the major paths of carbon in photorespiratory mutants of synechocystis.
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DOI：
10.1371/journal.pone.0016278
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发表时间：
2011-01-21
期刊：
影响因子：
3.7
通讯作者：
Kopka J
中科院分区：
文献类型：
--
作者：
Huege J;Goetze J;Schwarz D;Bauwe H;Hagemann M;Kopka J
最近利用野生型和基因缺失突变体的转录本和代谢物图谱的研究表明，光呼吸途径对聚球藻的生长是必不可少的。大气条件下的PCC 6803。初级代谢物，如甘氨酸和乙醇酸的池大小变化，表明与光呼吸有关。分析了聚球藻自养培养中初级代谢产物的~(13)C标记动力学。用气相色谱-质谱仪(GC-MS)对PCC6803与光呼吸的关系进行了研究。预先适应高二氧化碳(5%，HC)或有限二氧化碳(0.035%，LC)条件的细胞在非常高(2%w/w)13C-NaHCO3(VHC)条件下进行脉冲标记，然后分别在HC和LC条件下用环境12C处理。对选定代谢物的13C浓集、池大小的相对变化和13C通量进行了评估。我们论证了集胞藻通过Rubisco同化二氧化碳的两条主要途径，即从3PGA通过PEP同化到天冬氨酸、苹果酸和柠檬酸，或者从3PGA通过葡萄糖-6-磷酸同化到蔗糖。结果揭示了碳从3PGA流向PEP池的证据。此外，在被认为抑制光呼吸的条件下观察到了乙醇酸的13C标记。使用积累乙醇酸的Δglcd1突变体，我们证明了在有利于光呼吸的条件下，13C增强分配到乙醇酸库，并增强13C分配到甘氨酸积累ΔgcvT突变体的甘氨酸库。在LC条件下，光呼吸突变体Δglcd1和ΔgcvT表现出额外的固碳PEP羧化酶途径的活性增强。通过我们的非稳态~(13)C标记方法和对具有相应~(13)C浓集的代谢物池大小的分析，我们确定了在高和低无机碳供应存在的情况下集胞藻碳同化的主要途径的使用和调节。
Recent studies using transcript and metabolite profiles of wild-type and gene deletion mutants revealed that photorespiratory pathways are essential for the growth of Synechocystis sp. PCC 6803 under atmospheric conditions. Pool size changes of primary metabolites, such as glycine and glycolate, indicated a link to photorespiration. The 13C labelling kinetics of primary metabolites were analysed in photoautotrophically grown cultures of Synechocystis sp. PCC 6803 by gas chromatography-mass spectrometry (GC-MS) to demonstrate the link with photorespiration. Cells pre-acclimated to high CO2 (5%, HC) or limited CO2 (0.035%, LC) conditions were pulse-labelled under very high (2% w/w) 13C-NaHCO3 (VHC) conditions followed by treatment with ambient 12C at HC and LC conditions, respectively. The 13C enrichment, relative changes in pool size, and 13C flux of selected metabolites were evaluated. We demonstrate two major paths of CO2 assimilation via Rubisco in Synechocystis, i.e., from 3PGA via PEP to aspartate, malate and citrate or, to a lesser extent, from 3PGA via glucose-6-phosphate to sucrose. The results reveal evidence of carbon channelling from 3PGA to the PEP pool. Furthermore, 13C labelling of glycolate was observed under conditions thought to suppress photorespiration. Using the glycolate-accumulating ΔglcD1 mutant, we demonstrate enhanced 13C partitioning into the glycolate pool under conditions favouring photorespiration and enhanced 13C partitioning into the glycine pool of the glycine-accumulating ΔgcvT mutant. Under LC conditions, the photorespiratory mutants ΔglcD1 and ΔgcvT showed enhanced activity of the additional carbon-fixing PEP carboxylase pathway. With our approach of non-steady-state 13C labelling and analysis of metabolite pool sizes with respective 13C enrichments, we identify the use and modulation of major pathways of carbon assimilation in Synechocystis in the presence of high and low inorganic carbon supplies.
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DOI：
10.1073/pnas.182432999
发表时间：
2002-09-17
影响因子：
11.1
作者：
Martin, W;Rujan, T;Penny, D
通讯作者：
Penny, D
影响因子：
7.4
作者：
KELLY, GJ;LATZKO, E
通讯作者：
LATZKO, E
影响因子：
7.4
作者：
Eisenhut, Marion;Huege, Jan;Hagemann, Martin
通讯作者：
Hagemann, Martin
影响因子：
2.2
作者：
Cegelski, L;Schaefer, J
通讯作者：
Schaefer, J
影响因子：
7.4
作者：
Eisenhut, Marion;Aguirre von Wobeser, Eneas;Hagemann, Martin
通讯作者：
Hagemann, Martin