论文标题
核糖异构化网络中的平衡和非平衡呋喃糖选择
Equilibrium and non-equilibrium furanose selection in the ribose isomerisation network
论文作者
论文摘要
鉴于吡喃糖的种类在平衡时基本上更稳定，在核酸中，$β$ -D-核呋喃糖在核酸中的独家存在仍然是一个难题。但是，仍然缺乏高于大约50 $^{\，\ rm o} $ c的相对呋喃糖/吡喃糖分数的精确表征。在这里，我们采用了NMR测量和统计力学建模的组合，以在高温下平衡时在平衡时预测呋喃糖和吡喃糖之间的种群反转。更重要的是，我们表明，稳定的温度梯度可以将开放的同组化网络引导到非平衡稳态中，在这种稳态中，在该稳态中，在平衡热力学设定的限制之外，Furanose的增加。此外，我们证明，在最佳耗散时，Furanose的非平衡选择是由温度梯度和异构化的能屏障所测量的。预测的最佳距离与与海底极其新鲜的熔岩流有关的热液通风孔中的温度下降兼容。
The exclusive presence of $β$-D-ribofuranose in nucleic acids is still a conundrum in prebiotic chemistry, given that pyranose species are substantially more stable at equilibrium. However, a precise characterisation of the relative furanose/pyranose fraction at temperatures higher than about 50$^{\,\rm o}$C is still lacking. Here, we employ a combination of NMR measurements and statistical mechanics modelling to predict a population inversion between furanose and pyranose at equilibrium at high temperatures. More importantly, we show that a steady temperature gradient may steer an open isomerisation network into a non-equilibrium steady state where furanose is boosted beyond the limits set by equilibrium thermodynamics. Moreover, we demonstrate that nonequilibrium selection of furanose is maximum at optimal dissipation, as gauged by the temperature gradient and energy barriers for isomerisation. The predicted optimum is compatible with temperature drops found in hydrothermal vents associated with extremely fresh lava flows on the seafloor.
