A Model Protometabolic Pathway across Protocell Membranes Assisted by Photocatalytic Minerals
A Model Protometabolic Pathway across Protocell Membranes Assisted by Photocatalytic Minerals
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DOI：
10.1021/acs.jpcc.9b10127
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发表时间：
2020-01-16
影响因子：
3.7
通讯作者：
Sahai, Nita
中科院分区：
文献类型：
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作者：
Dalai, Punam;Sahai, Nita
现代细胞膜的原始细胞类似物(脂泡)被认为是在地球早期从地球化学向生物化学转变的过程中参与原始代谢的隔室。将光能转化为化学能进行代谢是从最早的代谢向光营养转变的关键步骤。在这些过渡阶段，光催化矿物可能起到了酶的作用。在这里，我们展示了一个简单的光异养原代谢促进光催化矿物质穿过一个模型原细胞(囊泡)膜。囊外介质中的这些矿物质利用光能驱动耦合的多步骤跨膜电子转移反应(TMETR)，同时产生跨膜pH梯度，并将囊泡内的烟酰胺腺嘌呤二核苷酸(NAD(+))还原为NADH。质子梯度或化学渗透势可能为三磷酸腺苷(ATP)的合成提供了基础，而NADH可能已经潜在地推动了原细胞内进一步的代谢化学。
Protocell analogs (lipid vesicles) to modern cell membranes have been postulated as compartments that may have been involved in primordial metabolism during the transition from geochemistry to biochemistry on early Earth. The transduction of light energy into chemical energy for metabolism was a key step in the transition from the earliest metabolisms to phototrophy. Photocatalytic minerals may have served the role of enzymes during these transitional stages. Here, we demonstrate a simple photoheterotrophic protometabolism promoted by photocatalytic minerals across a model protocell (vesicle) membrane. These minerals in the extra-vesicular medium utilized light energy to drive a coupled, multistep transmembrane electron transfer reaction (TMETR), while simultaneously generating a transmembrane pH gradient and reducing nicotinamide adenine dinucleotide (NAD(+)) to NADH within the vesicle. The proton gradient or chemiosmotic potential could have provided a basis for adenosine triphosphate (ATP) synthesis and NADH could potentially have driven further metabolic chemistry inside the protocells.