Ganglioside embedded in reconstituted lipoprotein binds cholera toxin with elevated affinity

Area of Science:

• Biophysics
• Biochemistry
• Nanotechnology

Background:

• Exogenously presenting cell-surface receptors synthetically can protect cells from toxins.
• Improving synthetic receptor binding affinity is crucial, especially for polyvalent toxins where receptor clustering impedes binding.

Purpose of the Study:

• To demonstrate that reconstituted lipoproteins can enhance toxin-receptor binding affinity.
• To investigate the role of the receptor microenvironment in modulating binding.
• To assess the efficacy of this system in protecting mammalian cells from toxins.

Main Methods:

• Utilizing reconstituted lipoproteins (discoidal lipid bilayers bounded by apolipoprotein) functionalized with pathogen receptors.
• Employing a Foerster Resonance Energy Transfer (FRET)-based assay to measure binding affinity.
• Using wide-area epifluorescence to evaluate toxin diversion from mammalian cells.

Main Results:

• Reconstituted lipoproteins with ganglioside monosialotetrahexosylganglioside (GM1) showed significantly higher affinity for cholera toxin compared to liposomes or supported lipid bilayers.
• This enhanced binding is attributed to improved control over receptor clustering within the lipoprotein platform.
• The engineered assemblies effectively diverted cholera toxin from mammalian cells, demonstrating protective capabilities.

Conclusions:

• Reconstituted high-density lipoproteins can be engineered to incorporate pathogen receptors, altering their binding affinity.
• Attenuation of receptor aggregation within lipoproteins is a key factor in enhancing pathogen binding.
• These engineered lipoprotein assemblies serve as an effective strategy for cellular protection against biological toxins.