Cyclophospholipids Increase Protocellular Stability to Metal Ions

Abstract

<jats:p>&lt;p&gt;Model protocells have long been constructed with fatty acids, because these lipids are prebiotically plausible and can, at least theoretically, support a protocell life cycle. However, fatty acid protocells are stable only within a narrow range of pH and metal ion concentration. This instability is particularly problematic as the early Earth would have had a range of conditions, and life as we know it is completely reliant on metal ions for catalysis and the folding and activity of biological polymers. Here we show that prebiotically plausible monoacyl cyclophospholipids form robust vesicles that survive a broad range of pH and high concentrations of Mg2+, Ca2+, and Na+. Importantly, stability to Mg2+ and Ca2+ is improved by the presence of environmental concentrations of Na+. These results suggest that cyclophospholipids, or lipids with similar characteristics, may have played a central role during the emergence of Darwinian evolution.&lt;/p&gt;</jats:p>

Population-Level Membrane Diversity Triggers Growth and Division of Protocells

“…Although the differences in lipid composition that were used to drive growth were based on differences in the hydrophobic chains, computational models suggest that similar effects are likely to arise from differences in the lipid headgroup. 60 Modifications of the headgroup would be more chemically accessible 31 , 34 , 59 − 61 and thus would more easily tie into the chemical activity of the protocell. Since vesicles are capable of retaining entrapped nucleic acids during growth and division, such systems may have the potential to support Darwinian evolution.…”

Population-level Membrane Diversity Triggers Growth and Division of Protocells

“…Although the differences in lipid composition that were used to drive growth were based on differences in the hydrophobic chains, similar effects are likely to arise from differences in the lipid head-group. Modifications of the head-group would be more chemically accessible [37][38][39] and thus would more easily tie into the chemical activity of the protocell. Since the vesicles are capable of retaining entrapped nucleic acids during growth and division, such a system has the potential to support Darwinian evolution.…”

Artificial cells drive neural differentiation

“…For the analysis of toxicity and stability, the artificial cells were prepared as described in the “Generation of artificial cells” section. An aliquot of artificial cells was either purified on a sepharose 4b column as previously described ( 60 ) or analyzed by flow cytometry at 1:50 dilution. The same gating strategy was used as described in the “Flow cytometry” section.…”