Department of Chemistry and Chemical Biology , Harvard University 12 Oxford Street , Cambridge , Massachusetts 02138 , United States.
Institute for Molecules and Materials , Radboud University Nijmegen , Heyendaalseweg 1 35 , 6525 AJ Nijmegen , The Netherlands.
J Am Chem Soc. 2019 May 22;141(20):8289-8295. doi: 10.1021/jacs.9b02554. Epub 2019 May 9.
How simple chemical reactions self-assembled into complex, robust networks at the origin of life is unknown. This general problem-self-assembly of dissipative molecular networks-is also important in understanding the growth of complexity from simplicity in molecular and biomolecular systems. Here, we describe how heterogeneity in the composition of a small network of oscillatory organic reactions can sustain (rather than stop) these oscillations, when homogeneity in their composition does not. Specifically, multiple reactants in an amide-forming network sustain oscillation when the environment (here, the space velocity) changes, while homogeneous networks-those with fewer reactants-do not. Remarkably, a mixture of two reactants of different structure-neither of which produces oscillations individually-oscillates when combined. These results demonstrate that molecular heterogeneity present in mixtures of reactants can promote rather than suppress complex behaviors.
在生命起源时，简单的化学反应如何自行组装成复杂而稳健的网络，目前尚不清楚。这个一般性问题——耗散分子网络的自组装——对于理解分子和生物分子系统中从简单到复杂的复杂性增长也很重要。在这里，我们描述了在组成小的振荡有机反应网络的组成存在异质时，这些振荡如何得以维持（而不是停止），而在组成同质时则不会。具体来说，酰胺形成网络中的多种反应物在环境（这里是空间速度）变化时维持振荡，而组成均一的网络——反应物较少的网络——则不会。值得注意的是，两种结构不同的反应物的混合物——单独一种都不会产生振荡——结合时会振荡。这些结果表明，反应物混合物中存在的分子异质性可以促进而不是抑制复杂行为。
