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Construction of artificial cells requires the development of straightforward methods for mimicking natural phospholipid membrane formation. Here we describe the use of direct aminolysis ligations to spontaneously generate biomimetic phospholipid membranes from water-soluble starting materials. Additionally, we explore the suitability of such biomimetic approaches for driving the in situ formation of native phospholipid membranes. Our studies suggest that non-enzymatic ligation reactions could have been important for the synthesis of phospholipid-like membranes during the origin of life, and might be harnessed as simplified methods to enable the generation of lipid compartments in artificial cells. 

There has been increasing interest in methods to generate synthetic lipid membranes as key constituents of artificial cells or to develop new tools for remodeling membranes in living cells. However, the biosynthesis of phospholipids involves elaborate enzymatic pathways that are challenging to reconstitute in vitro. An alternative approach is to use chemical reactions to non‐enzymatically generate natural or non‐canonical phospholipids de novo. Previous reports have shown that synthetic lipid membranes can be formed in situ using various ligation chemistries, but these methods lack biocompatibility and/or suffer from slow kinetics at physiological pH. Thus, it would be valuable to develop chemoselective strategies for synthesizing phospholipids from water‐soluble precursors that are compatible with synthetic or living cells Here, we demonstrate that amide‐forming ligations between lipid precursors bearing hydroxylamines and α‐ketoacids (KAs) or potassium acyltrifluoroborates (KATs) can be used to prepare non‐canonical phospholipids at physiological pH conditions. The generated amide‐linked phospholipids spontaneously self‐assemble into cell‐like micron‐sized vesicles similar to natural phospholipid membranes. We show that lipid synthesis using KAT ligation proceeds extremely rapidly, and the high selectivity and biocompatibility of the approach facilitates the in situ synthesis of phospholipids and associated membranes in living cells.

 

There has been increasing interest in methods to generate synthetic lipid membranes as key constituents of artificial cells or to develop new tools for remodeling membranes in living cells. However, the biosynthesis of phospholipids involves elaborate enzymatic pathways that are challenging to reconstitute in vitro. An alternative approach is to use chemical reactions to non‐enzymatically generate natural or non‐canonical phospholipids de novo. Previous reports have shown that synthetic lipid membranes can be formed in situ using various ligation chemistries, but these methods lack biocompatibility and/or suffer from slow kinetics at physiological pH. Thus, it would be valuable to develop chemoselective strategies for synthesizing phospholipids from water‐soluble precursors that are compatible with synthetic or living cells Here, we demonstrate that amide‐forming ligations between lipid precursors bearing hydroxylamines and α‐ketoacids (KAs) or potassium acyltrifluoroborates (KATs) can be used to prepare non‐canonical phospholipids at physiological pH conditions. The generated amide‐linked phospholipids spontaneously self‐assemble into cell‐like micron‐sized vesicles similar to natural phospholipid membranes. We show that lipid synthesis using KAT ligation proceeds extremely rapidly, and the high selectivity and biocompatibility of the approach facilitates the in situ synthesis of phospholipids and associated membranes in living cells.