Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794.
Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.
Proc Natl Acad Sci U S A. 2017 Sep 5;114(36):E7460-E7468. doi: 10.1073/pnas.1620179114. Epub 2017 Aug 22.
It is not known how life originated. It is thought that prebiotic processes were able to synthesize short random polymers. However, then, how do short-chain molecules spontaneously grow longer? Also, how would random chains grow more informational and become autocatalytic (i.e., increasing their own concentrations)? We study the folding and binding of random sequences of hydrophobic ([Formula: see text]) and polar ([Formula: see text]) monomers in a computational model. We find that even short hydrophobic polar () chains can collapse into relatively compact structures, exposing hydrophobic surfaces. In this way, they act as primitive versions of today's protein catalysts, elongating other such HP polymers as ribosomes would now do. Such foldamer catalysts are shown to form an autocatalytic set, through which short chains grow into longer chains that have particular sequences. An attractive feature of this model is that it does not overconverge to a single solution; it gives ensembles that could further evolve under selection. This mechanism describes how specific sequences and conformations could contribute to the chemistry-to-biology (CTB) transition.
生命是如何起源的尚不清楚。人们认为前生物过程能够合成短的随机聚合物。然而，那么，短链分子如何自发地变长呢？此外，随机链如何变得更具信息性并成为自我催化的（即增加自身浓度）？我们在计算模型中研究了疏水（[Formula: see text]）和极性（[Formula: see text]）单体的随机序列的折叠和结合。我们发现，即使是短的疏水-极性（HP）链也可以折叠成相对紧凑的结构，暴露出疏水面。通过这种方式，它们充当了当今蛋白质催化剂的原始版本，就像核糖体现在所做的那样，延伸其他 HP 聚合物。事实证明，这种折叠体催化剂形成了一个自我催化集，通过该集，短链可以生长成具有特定序列的更长链。该模型的一个吸引人的特点是它不会过度收敛到单个解决方案；它提供了可以在选择下进一步进化的集合。该机制描述了特定序列和构象如何有助于化学到生物学（CTB）的转变。
