Kloprogge Jacob Teunis Theo, Hartman Hyman
School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, Miagao 5023, Philippines.
Life (Basel). 2022 Feb 9;12(2):259. doi: 10.3390/life12020259.
There are three groups of scientists dominating the search for the origin of life: the organic chemists (the Soup), the molecular biologists (RNA world), and the inorganic chemists (metabolism and transient-state metal ions), all of which have experimental adjuncts. It is time for Clays and the Origin of Life to have its experimental adjunct. The clay data coming from Mars and carbonaceous chondrites have necessitated a review of the role that clays played in the origin of life on Earth. The data from Mars have suggested that Fe-clays such as nontronite, ferrous saponites, and several other clays were formed on early Mars when it had sufficient water. This raised the question of the possible role that these clays may have played in the origin of life on Mars. This has put clays front and center in the studies on the origin of life not only on Mars but also here on Earth. One of the major questions is: What was the catalytic role of Fe-clays in the origin and development of metabolism here on Earth? First, there is the recent finding of a chiral amino acid (isovaline) that formed on the surface of a clay mineral on several carbonaceous chondrites. This points to the formation of amino acids on the surface of clay minerals on carbonaceous chondrites from simpler molecules, e.g., CO, NH, and HCN. Additionally, there is the catalytic role of small organic molecules, such as dicarboxylic acids and amino acids found on carbonaceous chondrites, in the formation of Fe-clays themselves. Amino acids and nucleotides adsorb on clay surfaces on Earth and subsequently polymerize. All of these observations and more must be subjected to strict experimental analysis. This review provides an overview of what has happened and is now happening in the experimental clay world related to the origin of life. The emphasis is on smectite-group clay minerals, such as montmorillonite and nontronite.
有机化学家（“原始汤”理论）、分子生物学家（“RNA世界”假说）和无机化学家（新陈代谢与瞬态金属离子理论），他们都有相关的实验辅助。现在是时候让《黏土与生命起源》也拥有其实验辅助了。来自火星和碳质球粒陨石的黏土数据促使人们重新审视黏土在地球生命起源中所起的作用。来自火星的数据表明，诸如绿脱石、亚铁皂石等含铁黏土以及其他几种黏土是在早期火星有充足水分时形成的。这就引出了这些黏土可能在火星生命起源中所起作用的问题。这使得黏土在火星乃至地球生命起源的研究中处于前沿和中心位置。其中一个主要问题是：含铁黏土在地球新陈代谢的起源和发展中起到了什么催化作用？首先，最近在几块碳质球粒陨石上发现一种手性氨基酸（异缬氨酸）在黏土矿物表面形成。这表明在碳质球粒陨石的黏土矿物表面，由更简单的分子，如一氧化碳、氨和氰化氢，形成了氨基酸。此外，碳质球粒陨石上发现的二元羧酸和氨基酸等小分子有机物在含铁黏土自身形成过程中具有催化作用。在地球上，氨基酸和核苷酸吸附在黏土表面，随后发生聚合。所有这些观察结果以及更多情况都必须经过严格的实验分析。这篇综述概述了与生命起源相关的实验性黏土领域中已经发生和正在发生的事情。重点是蒙脱石族黏土矿物，如蒙脱石和绿脱石。
