13C NMR spectroscopy of Methanobacterium thermoautotrophicum. Carbon fluxes and primary metabolic pathways.
13C NMR spectroscopy of Methanobacterium thermoautotrophicum. Carbon fluxes and primary metabolic pathways.
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DOI：
10.1016/s0021-9258(18)66569-x
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发表时间：
1986-12
期刊：
影响因子：
--
通讯作者：
J. N. Evans;D. Raleigh;C. Tolman;M. Roberts
中科院分区：
文献类型：
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作者：
J. N. Evans;D. Raleigh;C. Tolman;M. Roberts
从可溶性代谢产物2，3-环焦磷酸甘油酸酯（CPP），一种新的化合物，发现在高浓度的甲烷细菌和甲烷短杆菌，到含碳水化合物的材料的13 C-标记的碳通量已推导出固态13 C NMR光谱，这强烈主张在这一独特的代谢产物的产甲烷作用。周转率，但不是稳态水平，标记的CPP由13 CO2或[13 C]醋酸显着依赖于细胞生长条件。当对碳水化合物合成的需求减少时（即在稳定期），CPP生物合成和降解的速率降低10倍，并且二糖α，α-海藻糖积累。缬氨霉素，一种代谢抑制剂甲烷热自养菌生长，不影响稳态水平的CPP，但减少13 C摄取到CPP池。这些不同条件对CPP标记的影响表明CPP与细胞代谢有关的严格调节。用[6-（13）C]葡萄糖标记CPP，其不作为该生物体的能量或碳源，提供了强有力的证据，即葡萄糖通过逆转的异源生成途径被裂解。这种连接葡萄糖与磷酸丙糖型前体的代谢途径以及通过用[U-13 C]葡萄糖孵育细胞标记的CPP的13 C NMR光谱的分析已经确定，体内磷酸烯醇丙酮酸合成酶必须是可逆的。
The flux of 13C-labeled carbons from the soluble metabolite 2,3-cyclopyrophosphoglycerate (CPP), a novel compound found in high concentrations exclusively in methanobacteria and methanobrevibacter, into carbohydrate-containing material has been deduced by solid-state 13C NMR spectroscopy which strongly argues for a role in gluconeogenesis for this unique metabolite. The turnover rates, but not the steady-state levels, of CPP labeled by 13CO2 or [13C]acetate depend dramatically on cell growth conditions. When the demand for carbohydrate synthesis is reduced (i.e. in stationary phase), the rates of CPP biosynthesis and degradation decrease 10-fold, and the disaccharide alpha, alpha-trehalose accumulates. Valinomycin, a metabolic inhibitor of Methanobacterium thermoautotrophicum growth, does not affect steady-state levels of CPP, but does decrease 13C uptake into the CPP pool. The effects of these different conditions on CPP labeling suggest stringent regulation of CPP linked to cellular metabolism. Labeling of CPP by [6-(13)C]glucose, which does not serve as an energy or carbon source for this organism, provides strong evidence that glucose is cleaved by the reverse of the gluconeogenesis pathway. This metabolic pathway linking glucose with triose phosphate type precursors and an analysis of the 13C NMR spectrum of CPP labeled by incubating cells with [U-13C]glucose have established that in vivo phosphoenolpyruvate synthetase must be reversible.