Department of Genetics, Evolution and Environment, University College London, London, UK.
Bioessays. 2010 Apr;32(4):271-80. doi: 10.1002/bies.200900131.
Despite thermodynamic, bioenergetic and phylogenetic failings, the 81-year-old concept of primordial soup remains central to mainstream thinking on the origin of life. But soup is homogeneous in pH and redox potential, and so has no capacity for energy coupling by chemiosmosis. Thermodynamic constraints make chemiosmosis strictly necessary for carbon and energy metabolism in all free-living chemotrophs, and presumably the first free-living cells too. Proton gradients form naturally at alkaline hydrothermal vents and are viewed as central to the origin of life. Here we consider how the earliest cells might have harnessed a geochemically created proton-motive force and then learned to make their own, a transition that was necessary for their escape from the vents. Synthesis of ATP by chemiosmosis today involves generation of an ion gradient by means of vectorial electron transfer from a donor to an acceptor. We argue that the first donor was hydrogen and the first acceptor CO2.
尽管热力学、生物能量学和系统发生学存在缺陷，但原始汤这一已有 81 年历史的概念仍然是主流生命起源理论的核心。但是，汤在 pH 值和氧化还原电位上是均匀的，因此没有通过化学渗透偶联进行能量耦合的能力。热力学限制使得化学渗透偶联对于所有自由生活的化能营养生物的碳和能量代谢都是严格必需的，大概对于最初的自由生活细胞也是如此。质子梯度在碱性热液喷口自然形成，被认为是生命起源的核心。在这里，我们考虑早期细胞如何利用地球化学产生的质子动力，然后学会自己产生质子动力，这种转变对于它们从喷口逃脱是必要的。今天，通过化学渗透合成 ATP 需要通过从供体到受体的向量电子转移来产生离子梯度。我们认为，第一个供体是氢，第一个受体是二氧化碳。
