Extreme accumulation of nucleotides in simulated hydrothermal pore systems
Extreme accumulation of nucleotides in simulated hydrothermal pore systems
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DOI：
10.1073/pnas.0609592104
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发表时间：
2007-05-29
影响因子：
11.1
通讯作者：
Braun, Dieter
中科院分区：
文献类型：
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作者：
Baaske, Philipp;Weinert, Franz M.;Braun, Dieter
我们模拟了在热梯度影响下的细长热液孔隙系统中的分子输运。我们发现在各种各样的堵塞的孔隙中分子的极端积累。该机制能够提供高浓度的单核苷酸，适用于生命起源时RNA世界的运作。它仅由穿过孔隙的热梯度驱动。一方面，流体通过热对流沿着沿着穿梭，而另一方面，分子在热扩散的驱动下漂移穿过孔隙。结果，毫米大小的孔甚至将超过10（8）倍的单个核苷酸积累到微米大小的区域中。在孔的封闭底端附近的本体水中发现分子的浓度增加。由于累积指数依赖于孔长度和温度差，它是相当强大的裂缝的几何形状和分子尺寸的变化。而薄的孔只能浓缩长的多核苷酸，较厚的孔同样很好地积累短的和长的多核苷酸，并允许各种分子组成。这种设置还提供了温度振荡，先前显示在蛋白质辅助PCR中以指数方式复制DNA。我们的研究结果表明，生命的进化，复杂的主动膜运输是不需要的初始步骤。我们发现，在一个热梯度互连的矿物孔隙提供了一个引人注目的高浓度的生命分子进化的起点。
We simulate molecular transport in elongated hydrothermal pore systems influenced by a thermal gradient. We find extreme accumulation of molecules in a wide variety of plugged pores. The mechanism is able to provide highly concentrated single nucleotides, suitable for operations of an RNA world at the origin of life. It is driven solely by the thermal gradient across a pore. On the one hand, the fluid is shuttled by thermal convection along the pore, whereas on the other hand, the molecules drift across the pore, driven by thermodiffusion. As a result, millimeter-sized pores accumulate even single nucleotides more than 10(8)-fold into micrometer-sized regions. The enhanced concentration of molecules is found in the bulk water near the closed bottom end of the pore. Because the accumulation depends exponentially on the pore length and temperature difference, it is considerably robust with respect to changes in the cleft geometry and the molecular dimensions. Whereas thin pores can concentrate only long polynucleotides, thicker pores accumulate short and long polynucleotides equally well and allow various molecular compositions. This setting also provides a temperature oscillation, shown previously to exponentially replicate DNA in the protein-assisted PCR. Our results indicate that, for life to evolve, complicated active membrane transport is not required for the initial steps. We find that interlinked mineral pores in a thermal gradient provide a compelling high-concentration starting point for the molecular evolution of life.