Formation mechanism of thermally controlled pH gradients

被引:6
|
作者
Matreux, Thomas [1 ]
Altaner, Bernhard [2 ]
Raith, Johannes [2 ]
Braun, Dieter [1 ]
Mast, Christof B. B. [1 ]
Gerland, Ulrich [2 ]
机构
[1] Ludwig Maximilian Univ Munich, Syst Biophys, D-80799 Munich, Germany
[2] Tech Univ Munich, Phys Complex Biosyst, D-85748 Garching, Germany
关键词
POSSIBLE PREBIOTIC SYNTHESIS; FORMIC-ACID; ORIGIN; PURINE; ELECTRONEUTRALITY; TEMPERATURE; REPLICATION; CHEMISTRY; FORMAMIDE; CONSTANT;
D O I
10.1038/s42005-023-01126-y
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Cells use pH gradients to drive the synthesis of adenosine triphosphate (ATP), but the physicochemical mechanisms that can produce pH gradients in non-equilibrium settings are poorly understood. The authors here theoretically and experimentally investigate the formation of a pH gradient in an acid-base reaction system, driven by a heat flow, providing insights on how crude non-equilibrium systems can feed chemical gradients exploitable by life. Spatial proton gradients create energy in biological systems and are likely a driving force for prebiotic systems. Due to the fast diffusion of protons, they are however difficult to create as steady state, unless driven by other non-equilibria such as thermal gradients. Here, we quantitatively predict the heat-flux driven formation of pH gradients for the case of a simple acid-base reaction system. To this end, we (i) establish a theoretical framework that describes the spatial interplay of chemical reactions with thermal convection, thermophoresis, and electrostatic forces by a separation of timescales, and (ii) report quantitative measurements in a purpose-built microfluidic device. We show experimentally that the slope of such pH gradients undergoes pronounced amplitude changes in a concentration-dependent manner and can even be inverted. The predictions of the theoretical framework fully reflect these features and establish an understanding of how naturally occurring non-equilibrium environmental conditions can drive pH gradients.
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页数:9
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