Did Nature use Reduced Oxidation State Phosphorus in Prebiotic Chemistry? Strengthening the Case for a Non-Phosphate World prior to the RNA-World

磷酸盐是地球上所有生命的关键成分。磷酸盐在地球上无处不在，我们把它作为一种钙盐从地下挖出来，我们用它来刷牙，我们每天在食物和饮料中消费它。然而，尽管磷酸盐是一种相当常见的化学物质，但它绝不能确定大自然选择磷酸盐作为地球上最早的生命形式。很大一部分问题是，磷酸盐化学品在化学上既极难溶解，又非常不具活性。1955年，科学家Addison Gulick提出，如果早期地球上有其他形式的磷，这个磷酸盐问题本可以得到解决。这些化学物质称为磷酸盐和亚膦酸盐，是磷酸盐的近亲，但在水中更易溶，化学活性也更强。问题是，磷酸盐和磷酸盐在今天的地球上并不为人所知，因为数千年来，地球的化学环境已经发生了如此大的变化，以至于现在只有磷酸盐是稳定的。然而，我们最近发现，在早期地球上，通过富含铁的陨石与水在光的存在下发生化学反应，亚磷酸盐和亚膦酸盐很容易被生命前化学所利用。这一发现使我们能够首次详细探索磷酸盐和磷酸盐在生命起源问题上的潜力，并在一定程度上相信这种化学物质可能在早期地球上存在。该项目由两部分组成。在第一部分中，我们将详细了解实际陨石碎片的化学修饰是如何形成磷酸盐和亚膦酸盐的。在第二部分中，我们探索了在早期地球上可能与这两种磷物种发生的潜在化学反应，以及这些化学反应可能会对一些关键生物分子，如益生菌有机磷聚合物的出现产生影响。

Phosphate is a key ingredient in all life on Earth. Phosphate is everywhere on Earth, we dig it out of the ground as a calcium salt, we use it to brush our teeth, we consume it in food and drink every day. However, despite it being a rather common chemical, it is by no means certain that Nature chose phosphate for the earliest forms of life on Earth. A large part of the problem is that phosphate chemicals are both extremely insoluble and very unreactive chemically. In 1955, the scientist Addison Gulick proposed that this phosphate problem could have been solved if other forms of phosphorus were available on the early Earth. These chemicals, called phosphonates and phosphinates, are close relatives of phosphate but are both more soluble and chemically reactive in water. The problem is that phosphonates and phosphinates are unkown on Earth today because over the millennia, the chemical environment of Earth has changed to such a degree that only phosphates are now stable. However, we have recently discovered that phosphinates and phosphonates could have been readily available to prebiotic chemistry on the early Earth through chemical reactions of iron-rich meteorites with water in the presence of light. This discovery allows us to explore in detail the potential of phosphonates and phosphinates in the origin-of-life problem for the first time with a degree of confidence that such chemistry could have been available on the early Earth.This project is built in two parts. In Part 1 we will look in detail at how exactly phosphonates and phosphinates were formed from the chemical modification of actual meteorite fragments. In Part 2, we explore potential chemical reactions which could have taken place on an early Earth with these two phosphorus species and which could have an impact in how some of key biological molecules, such as prebiotic organic phosphorus polymers, might have emerged.