13C-MFA delineates the photomixotrophic metabolism of Synechocystis sp PCC 6803 under light-and carbon-sufficient conditions
13C-MFA delineates the photomixotrophic metabolism of Synechocystis sp PCC 6803 under light-and carbon-sufficient conditions
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DOI：
10.1002/biot.201300477
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发表时间：
2014-05-01
影响因子：
4.7
通讯作者：
Tang, Yinjie J.
中科院分区：
文献类型：
--
作者：
You, Le;Berla, Bert;Tang, Yinjie J.
蓝藻的中心碳代谢是有争议的。50多年来，由于缺乏-酮戊二酸脱氢酶，人们认为蓝藻具有不完整的三羧酸循环。最近的体外酶促实验表明，这个循环实际上可能是封闭的。目前的研究采用C-13同位素来描绘蓝细菌聚囊藻sp. PCC 6803的途径。通过追踪补充谷氨酸进入TCA循环的下游代谢物，我们观察到-酮戊二酸在体内直接转化为琥珀酸盐。此外，乙醛酸盐的同位素示踪没有显示功能性乙醛酸盐分流，乙醛酸盐被用于甘氨酸合成。然后用C-13-MFA分析光营养碳代谢在光和碳充足条件下的变化。我们观察到：(i)通过TCA循环反应（-酮戊二酸琥珀酸）的体内通量很小(
The central carbon metabolism of cyanobacteria is under debate. For over 50 years, the lack of -ketoglutarate dehydrogenase has led to the belief that cyanobacteria have an incomplete TCA cycle. Recent in vitro enzymatic experiments suggest that this cycle may in fact be closed. The current study employed C-13 isotopomers to delineate pathways in the cyanobacterium Synechocystis sp. PCC 6803. By tracing the incorporation of supplemented glutamate into the downstream metabolites in the TCA cycle, we observed a direct in vivo transformation of -ketoglutarate to succinate. Additionally, isotopic tracing of glyoxylate did not show a functional glyoxylate shunt and glyoxylate was used for glycine synthesis. The photomixotrophic carbon metabolism was then profiled with C-13-MFA under light and carbon-sufficient conditions. We observed that: (i) the in vivo flux through the TCA cycle reactions (-ketoglutarate succinate) was minimal (