Encapsulation of protein/DNA complexes into unilamellar liposomes via annexin-mediated membrane recruitment and sonication.

This paper reports an effective protocol to encapsulate native protein/DNA complexes into unilamellar vesicles composed of natural lipids without the use of organic solvents, in physiological buffers, and at low protein/DNA concentrations. DNA compaction is achieved with the human mitochondrial transcription factor A (TFAM), which forms complexes (TFAMoplexes) when mixed with plasmid DNA (pDNA). The complexes are recruited to the surface of preformed giant unilamellar vesicles (GUVs) with the help of human annexin A4 and thereby concentrated at the membranes. This is followed by transforming the TFAMoplex-coated GUVs into small vesicles using short sonication pulses. This method results in the encapsulation of around 40% of the TFAMoplexes into unilamellar liposomes with an average hydrodynamic diameter of 121 nm. By harnessing the functions of human proteins, this approach enables the creation of complex molecular assemblies that will pave the way for a wide array of biochemical and biomedical applications.