Sci Rep. 2012;2:283. doi: 10.1038/srep00283. Epub 2012 Feb 22.
Cell-sized water-in-oil droplet covered by a lipid layer was used to understand how lipid membranes affect biochemical systems in living cells. Here, we report a remarkable acceleration of gene expression in a cell-sized water-in-oil droplet entrapping a cell-free translation system to synthesize GFP (green fluorescent protein). The production rate of GFP (V(GFP)) in each droplet remained almost constant at least for on the order of a day, which implies 0(th)-order reaction kinetics. Interestingly, V(GFP) was inversely proportional to radius of droplets (R) when R is under 50 μm, and V(GFP) in droplets with R ∼ 10 μm was more than 10 times higher than that in the bulk. The acceleration rates of GFP production in cell-sized droplets strongly depended on the lipid types. These results demonstrate that the membrane surface has the significant effect to facilitate protein production, especially when the scale of confinement is on the order of cell-size.
细胞大小的油包水乳滴被脂质层覆盖，用于了解脂质膜如何影响活细胞中的生化系统。在这里，我们报告了在细胞大小的油包水乳液中包裹无细胞翻译系统来合成 GFP（绿色荧光蛋白）的基因表达的显著加速。每个液滴中 GFP 的产生速率（V(GFP)）在至少一天的时间内几乎保持不变，这意味着是 0 级反应动力学。有趣的是，当 R 小于 50μm 时，V(GFP)与液滴半径（R）成反比，而 R 约为 10μm 的液滴中的 V(GFP)比在体相中的 V(GFP)高 10 倍以上。在细胞大小的液滴中 GFP 产量的加速率强烈依赖于脂质类型。这些结果表明，膜表面具有促进蛋白质产生的显著效果，特别是当限制的规模在细胞大小的量级时。
