Black Roy A, Blosser Matthew C
Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK.
Life (Basel). 2016 Aug 11;6(3):33. doi: 10.3390/life6030033.
We propose that the first step in the origin of cellular life on Earth was the self-assembly of fatty acids with the building blocks of RNA and protein, resulting in a stable aggregate. This scheme provides explanations for the selection and concentration of the prebiotic components of cells; the stabilization and growth of early membranes; the catalysis of biopolymer synthesis; and the co-localization of membranes, RNA and protein. In this article, we review the evidence and rationale for the formation of the proposed aggregate: (i) the well-established phenomenon of self-assembly of fatty acids to form vesicles; (ii) our published evidence that nucleobases and sugars bind to and stabilize such vesicles; and (iii) the reasons why amino acids likely do so as well. We then explain how the conformational constraints and altered chemical environment due to binding of the components to the membrane could facilitate the formation of nucleosides, oligonucleotides and peptides. We conclude by discussing how the resulting oligomers, even if short and random, could have increased vesicle stability and growth more than their building blocks did, and how competition among these vesicles could have led to longer polymers with complex functions.
我们提出，地球上细胞生命起源的第一步是脂肪酸与RNA和蛋白质的组成单元进行自组装，从而形成一个稳定的聚集体。该方案解释了细胞益生元成分的选择和浓缩、早期细胞膜的稳定与生长、生物聚合物合成的催化作用，以及细胞膜、RNA和蛋白质的共定位。在本文中，我们回顾了形成上述聚集体的证据和基本原理：（i）脂肪酸自组装形成囊泡这一已被充分证实的现象；（ii）我们已发表的证据表明，核碱基和糖类能够结合并稳定此类囊泡；（iii）氨基酸也可能如此的原因。接着，我们解释了由于各成分与膜结合而产生的构象限制和化学环境改变如何促进核苷、寡核苷酸和肽的形成。我们最后讨论了由此产生的寡聚物，即便短小且随机，如何比其组成单元更能提高囊泡的稳定性和促进其生长，以及这些囊泡之间的竞争如何导致具有复杂功能的更长聚合物的形成。
