Collaboration between primitive cell membranes and soluble catalysts

Abstract

One widely held model of early life suggests primitive cells consisted of simple RNA-based catalysts within lipid compartments. One possible selective advantage conferred by an encapsulated catalyst is stabilization of the compartment, resulting from catalyst-promoted synthesis of key membrane components. Here we show model protocell vesicles containing an encapsulated enzyme that promotes the synthesis of simple fatty acid derivatives become stabilized to Mg2+, which is required for ribozyme activity and RNA synthesis. Thus, protocells capable of such catalytic transformations would have enjoyed a selective advantage over other protocells in high Mg2+ environments. The synthetic transformation requires both the catalyst and vesicles that solubilize the water-insoluble precursor lipid. We suggest that similar modified lipids could have played a key role in early life, and that primitive lipid membranes and encapsulated catalysts, such as ribozymes, may have acted in conjunction with each other, enabling otherwise-impossible chemical transformations within primordial cells.

Functional Cellular Mimics for the Spatiotemporal Control of Multiple Enzymatic Cascade Reactions

“…[18] It provides unique prospects for future therapeutic applications from enzyme therapy to self-regulating bioreactors, especially to overcome deficient cellular enzymatic activities for diseases on the cellular and subcellular levels. [18] It provides unique prospects for future therapeutic applications from enzyme therapy to self-regulating bioreactors, especially to overcome deficient cellular enzymatic activities for diseases on the cellular and subcellular levels.…”

Response‐Retaliation Behavior in Synthetic Protocell Communities

“…Dispersed communities of synthetic protocells based on mixed populations of lipid vesicles, [1,2] polymersomes, [3,4] colloidosomes, [5] proteinosomes, [6] and coacervate microdroplets [7][8][9] provide an attractive opportunity to develop functionally interactive microcompartmentalized systems capable of chemical communication, [10][11][12][13][14][15][16][17] sensing, [18] signal-induced differentiation, [19,20] distributed computing, [21] oligonucleotide trafficking, [22] and enzyme-powered buoyancy. [23] Increasing the complexity of these consortia by exploiting matter and energy fluxes to drive cognate interactions remains ak ey challenge and ac ritical step towards synthetic protocell ecosystems exhibiting higher order contact-dependent behavior, such as artificial phagocytosis [24,25] and prototissue assembly.…”

Compartmentalized RNA catalysis in membrane - free coacervate protocells

“…Up-concentration and localization could have enabled RNA to function both as a catalyst (ribozyme) and storage medium for genetic information, as required by the RNA world hypothesis. 19 To date, ribozymes have been encapsulated within eutectic ice phases 20,21 and protocell models such as water-oil-droplets for directed evolution experiments, [22][23][24] membrane-bound lipid vesicles, [25][26][27] and membrane free compartments based on PEG/Dextran aqueous two-phase systems (ATPS). 28 Interestingly, RNA catalysis within ATPS exhibits an increased rate of reaction as a result of the increased concentration within the dextran phase.…”