School of Chemical &Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
School of Chemistry &Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Nat Chem. 2017 Apr;9(4):318-324. doi: 10.1038/nchem.2628. Epub 2016 Oct 10.
Many hypotheses concerning the nature of early life assume that genetic information was once transferred through the template-directed synthesis of RNA, before the emergence of coded enzymes. However, attempts to demonstrate enzyme-free, template-directed synthesis of nucleic acids have been limited by 'strand inhibition', whereby transferring information from a template strand in the presence of its complementary strand is inhibited by the stability of the template duplex. Here, we use solvent viscosity to circumvent strand inhibition, demonstrating information transfer from a gene-length template (>300 nt) within a longer (545 bp or 3 kb) duplex. These results suggest that viscous environments on the prebiotic Earth, generated periodically by water evaporation, could have facilitated nucleic acid replication-particularly of long, structured sequences such as ribozymes. Our approach works with DNA and RNA, suggesting that viscosity-mediated replication is possible for a range of genetic polymers, perhaps even for informational polymers that may have preceded RNA.
许多关于早期生命本质的假说假设，在编码酶出现之前，遗传信息曾通过 RNA 的模板指导合成进行传递。然而，尝试证明无酶、模板指导的核酸合成受到“链抑制”的限制，即在其互补链存在的情况下，从模板链转移信息会受到模板双链体稳定性的抑制。在这里，我们使用溶剂粘度来规避链抑制，证明了在较长的（545bp 或 3kb）双链体中，从基因长度的模板（>300nt）内进行信息传递。这些结果表明，前生物地球上由水蒸发周期性产生的粘性环境可能促进了核酸复制-特别是像核酶这样的长而结构化的序列。我们的方法适用于 DNA 和 RNA，表明粘度介导的复制对于一系列遗传聚合物是可能的，甚至对于可能先于 RNA 的信息聚合物也是可能的。
