Saiardi Adolfo
Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
Life (Basel). 2017 Jun 5;7(2):24. doi: 10.3390/life7020024.
Phosphorus, as phosphate, plays a paramount role in biology. Since phosphate transfer reactions are an integral part of contemporary life, phosphate may have been incorporated into the initial molecules at the very beginning. To facilitate the studies into early phosphate utilization, we should look retrospectively to phosphate-rich molecules present in today's cells. Overlooked by origin of life studies until now, inositol and the inositol phosphates, of which some species possess more phosphate groups that carbon atoms, represent ideal molecules to consider in this context. The current sophisticated association of inositol with phosphate, and the roles that some inositol phosphates play in regulating cellular phosphate homeostasis, intriguingly suggest that inositol might have played some role in the prebiotic process of phosphate exploitation. Inositol can be synthesized abiotically and, unlike glucose or ribose, is chemically stable. This stability makes inositol the ideal candidate for the earliest organophosphate molecules, as primitive inositol phosphates. I also present arguments suggesting roles for some inositol phosphates in early chemical evolution events. Finally, the possible prebiotic synthesis of inositol pyrophosphates could have generated high-energy molecules to be utilized in primitive trans-phosphorylating processes.
磷以磷酸盐的形式在生物学中起着至关重要的作用。由于磷酸转移反应是现代生命不可或缺的一部分，磷酸盐可能从一开始就被纳入了最初的分子中。为了便于对早期磷酸盐利用进行研究，我们应该回顾当今细胞中存在的富含磷酸盐的分子。肌醇和肌醇磷酸酯在生命起源研究中一直被忽视，其中一些种类的磷酸基团比碳原子还多，在这种情况下它们是值得考虑的理想分子。目前肌醇与磷酸盐之间复杂的关联，以及一些肌醇磷酸酯在调节细胞磷酸盐稳态中所起的作用，有趣地表明肌醇可能在磷酸盐利用的益生元过程中发挥了某种作用。肌醇可以通过非生物方式合成，并且与葡萄糖或核糖不同，它在化学上是稳定的。这种稳定性使肌醇成为最早的有机磷酸分子（即原始肌醇磷酸酯）的理想候选者。我还提出了一些论据，表明某些肌醇磷酸酯在早期化学进化事件中发挥的作用。最后，肌醇焦磷酸酯可能的益生元合成可能产生了高能分子，可用于原始的转磷酸化过程。
