Department of Bioengineering, University of California, San Diego, California, United States of America.
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
PLoS Comput Biol. 2022 Aug 17;18(8):e1010377. doi: 10.1371/journal.pcbi.1010377. eCollection 2022 Aug.
Identifying plausible mechanisms for compartmentalization and accumulation of the organic intermediates of early metabolic cycles in primitive cells has been a major challenge in theories of life's origins. Here, we propose a mechanism, where positive membrane potentials elevate the concentration of the organic intermediates. Positive membrane potentials are generated by positively charged surfaces of protocell membranes due to accumulation of transition metals. We find that (i) positive membrane potentials comparable in magnitude to those of modern cells can increase the concentration of the organic intermediates by several orders of magnitude; (ii) generation of large membrane potentials destabilize ion distributions; (iii) violation of electroneutrality is necessary to induce nonzero membrane potentials; and (iv) violation of electroneutrality enhances osmotic pressure and diminishes reaction efficiency, resulting in an evolutionary driving force for the formation of lipid membranes, specialized ion channels, and active transport systems.
确定原始细胞中早期代谢循环的有机中间体分隔和积累的合理机制一直是生命起源理论的主要挑战。在这里，我们提出了一种机制，其中正膜电势会提高有机中间体的浓度。由于过渡金属的积累，原细胞膜的带正电荷表面会产生正膜电势。我们发现：(i) 与现代细胞相当的正膜电势可以使有机中间体的浓度增加几个数量级；(ii) 大膜电势的产生会使离子分布不稳定；(iii) 为了产生非零的膜电势，有必要违反电中性；(iv) 违反电中性会增强渗透压并降低反应效率，从而为脂质膜、特殊离子通道和主动运输系统的形成提供进化驱动力。
