Do Soluble Phosphates Direct the Formose Reaction towards Pentose Sugars?
Do Soluble Phosphates Direct the Formose Reaction towards Pentose Sugars?
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DOI：
10.1089/ast.2021.0125
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发表时间：
2022-07-12
期刊：
影响因子：
4.2
通讯作者：
Lane, N.
中科院分区：
文献类型：
--
作者：
Camprubi, E.;Harrison, S. A.;Lane, N.
几十年来，甲醛糖反应一直是益生元合成糖（如核糖）的主要假设，但往往会产生糖和焦油的复杂混合物。将formose反应转化为生物学上有用的糖（如核糖）一直是生命起源研究的圣杯。在这里，我们测试的假设，一个简单的，prebiotically合理的磷酸化剂，乙酰磷酸，可以直接对核糖通过磷酸化的中间体的方式，类似于异生和戊糖磷酸途径的formose反应。我们确实发现，向发展中的甲醛糖反应中加入乙酰磷酸稳定了戊糖，包括核糖，使得在反应5小时后，与对照运行相比，剩余约10倍多的核糖。但使用液相色谱-质谱法进行的机理分析表明，甲醛糖反应非但没有通过磷酸化作用指向核糖，反而因Ca 2+离子沉淀为磷酸盐矿物（如磷灰石和羟基磷灰石）而停止。添加正磷酸盐也有同样的效果。当加入乙酰磷酸时，仅检测到磷酸化糖低于定量限。尽管如此，我们的发现并不完全是负面的。在地球化学上合理的条件下，与核糖在这些条件下的表观稳定性相结合的formose反应的敏感性，作为一个有价值的限制在生命起源的糖合成的可能途径。
The formose reaction has been a leading hypothesis for the prebiotic synthesis of sugars such as ribose for many decades but tends to produce complex mixtures of sugars and often tars. Channeling the formose reaction towards the synthesis of biologically useful sugars such as ribose has been a holy grail of origins-of-life research. Here, we tested the hypothesis that a simple, prebiotically plausible phosphorylating agent, acetyl phosphate, could direct the formose reaction towards ribose through phosphorylation of intermediates in a manner resembling gluconeogenesis and the pentose phosphate pathway. We did indeed find that addition of acetyl phosphate to a developing formose reaction stabilized pentoses, including ribose, such that after 5 h of reaction about 10-fold more ribose remained compared with control runs. But mechanistic analyses using liquid chromatography-mass spectrometry showed that, far from being directed towards ribose by phosphorylation, the formose reaction was halted by the precipitation of Ca2+ ions as phosphate minerals such as apatite and hydroxyapatite. Adding orthophosphate had the same effect. Phosphorylated sugars were only detected below the limit of quantification when adding acetyl phosphate. Nonetheless, our findings are not strictly negative. The sensitivity of the formose reaction to geochemically reasonable conditions, combined with the apparent stability of ribose under these conditions, serves as a valuable constraint on possible pathways of sugar synthesis at the origin of life.