Department of Biomolecular Engineering.
DigitalSpace Research, Boulder Creek, CA 95006, USA.
Life (Basel). 2015 Mar 13;5(1):872-87. doi: 10.3390/life5010872.
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution in dehydrated films on mineral surfaces followed by encapsulation and combinatorial selection in a hydrated bulk phase. The dehydrated phase can consist of concentrated eutectic mixtures or multilamellar liquid crystalline matrices. Both conditions organize and concentrate potential monomers and thereby promote polymerization reactions that are driven by reduced water activity in the dehydrated phase. In the case of multilamellar lipid matrices, polymers that have been synthesized are captured in lipid vesicles upon rehydration to produce a variety of molecular systems. Each vesicle represents a protocell, an "experiment" in a natural version of combinatorial chemistry. Two kinds of selective processes can then occur. The first is a physical process in which relatively stable molecular systems will be preferentially selected. The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization. Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life.
热液场在原始地球上是生物发生的候选环境。我们提出了一个模型，其中由水合和脱水循环驱动的分子系统在矿物表面的脱水膜中经历化学演化，然后在水合的本体相中进行封装和组合选择。脱水相可以由浓缩的共晶混合物或多层液晶基质组成。这两种条件都可以组织和浓缩潜在的单体，从而促进聚合反应，这些反应是由脱水相中降低的水活度驱动的。在多层脂质基质的情况下，在重新水合时，已经合成的聚合物被捕获在脂质泡囊中，从而产生各种分子系统。每个囊泡代表一个原细胞，这是组合化学的自然版本中的“实验”。然后可以发生两种类型的选择性过程。第一种是物理过程，其中相对稳定的分子系统将被优先选择。第二种是化学过程，其中封装聚合物的稀有组合形成能够捕获能量和营养物质以通过催化聚合进行生长的系统。在延长的时间跨度内持续循环，这种组合过程将产生具有生命基本特性的分子系统。
