Expression of Escherichia coli otsA in a Saccharomyces cerevisiae tps1 mutant restores trehalose 6-phosphate levels and partly restores growth and fermentation with glucose and control of glucose influx into glycolysis
Expression of Escherichia coli otsA in a Saccharomyces cerevisiae tps1 mutant restores trehalose 6-phosphate levels and partly restores growth and fermentation with glucose and control of glucose influx into glycolysis
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DOI：
10.1042/0264-6021:3500261
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发表时间：
2000-08-15
影响因子：
4.1
通讯作者：
Thevelein, JM
中科院分区：
文献类型：
--
作者：
Bonini, BM;van Vaeck, C;Thevelein, JM
TPS 1基因编码海藻糖-6-磷酸合酶（TPS），在酿酒酵母（Saccharomycescerevisiae）中对葡萄糖进入糖酵解过程发挥重要控制作用。TPS 1的缺失导致不能在葡萄糖上生长，因为糖磷酸盐的过度积累和ATP和磷酸盐的耗尽。我们表明，在酵母tps 1突变体中表达大肠杆菌同源物otsA导致高TPS活性。虽然海藻糖6-磷酸（Tre 6P）的水平在葡萄糖上的指数生长过程中至少与野生型酵母菌株一样高，但葡萄糖上的生长仅部分恢复，滞后期长得多。在加入葡萄糖后立即测量糖酵解代谢物显示，尽管有正常的Tre 6P积累，但仍存在糖磷酸的部分过度积累。与野生型菌株相比，通过额外缺失编码Tre 6P磷酸酶的TPS 2基因而导致的Tre 6P水平的强烈升高不能引起磷酸糖水平的强烈降低。此外，在恒化器实验中，对葡萄糖脉冲的短期反应被延迟，但在较长时间内恢复正常代谢。这些结果表明，从异源TPS酶合成Tre 6P可以在一定程度上恢复葡萄糖流入糖酵解的控制和酵母中葡萄糖上的生长。然而，他们也指出，酵母TPS酶，而不是E。coli otsA基因产物，能够增加Tre 6P控制葡萄糖流入酵母糖酵解的效率。
The TPS1 gene, encoding trehalose-6-phosphate synthase (TPS), exerts an essential control on the influx of glucose into glycolysis in the yeast Saccharomyces cerevisiae. The deletion of TPS1 causes an inability to grow on glucose because of a hyperaccumulation of sugar phosphates and depletion of ATP and phosphate, We show that expression of the Escherichia coli homologue, otsA, in a yeast tpsl mutant results in high TPS activity. Although the trehalose 6-phosphate (Tre6P) level durning exponential growth on glucose was at least as high as in a wildtype yeast strain, growth on glucose was only partly restored and the lag phase was much longer. Measurement of the glycolytic metabolites immediately after the addition of glucose showed that in spite of a normal Tre6P accumulation there was still a partial hyperaccumulation of sugar phosphates. Strong elevation of the Tre6P level by the additional deletion of the TPS2 gene, which encodes Tre6P phosphatase, was not able to cause a strong decrease in the sugar phosphate levels in comparison with the wild-type strain. In addition, in chemostat experiments the short-term response to a glucose pulse was delayed, but normal metabolism was regained over a longer period. These results show that Tre6P synthesis from a heterologous TPS enzyme can to some extent restore the control of glucose influx into glycolysis and growth on glucose in yeast. However, they also indicate that the yeast TPS enzyme, as opposed to the E. coli otsA gene product, is able to increase the efficiency of the Tre6P control on glucose influx into yeast glycolysis.