Reversible membrane deformations by straight DNA origami filaments

Area of Science:

• Biophysics
• Synthetic Biology
• Materials Science

Background:

• Cytoskeletal elements like actin and FtsZ form dynamic filaments that shape cellular membranes.
• Previous research utilized pre-curved DNA origami scaffolds to study membrane curvature.
• Mimicking straight filaments requires controlled polymerization and membrane interaction.

Purpose of the Study:

• To develop synthetic DNA origami scaffolds that emulate straight cytoskeletal filaments.
• To investigate the self-assembly and membrane-binding properties of these straight DNA origami filaments.
• To determine the role of filament formation in membrane shaping.

Main Methods:

• Design and synthesis of DNA origami nanostructures with cholesteryl anchors for membrane binding.
• Utilizing blunt end stacking interactions for controlled polymerization of DNA origami.
• Assessing nanostructure-membrane interactions using fluorescence microscopy and giant unilamellar vesicles.
• Investigating the effect of MgCl2 concentration on polymerization and depolymerization.

Main Results:

• DNA origami structures with blunt ends polymerized into linear filaments upon increasing MgCl2 concentration.
• These filaments could depolymerize upon decreasing MgCl2 concentration, demonstrating reversible assembly.
• High densities of membrane-bound filaments induced reversible, spike-like membrane protrusions on giant unilamellar vesicles.
• Membrane deformation correlated with MgCl2-triggered DNA origami polymerization.

Conclusions:

• Reversible polymerization of straight, membrane-bound filaments is achievable using DNA origami.
• The formation of these filaments is a minimal requirement for inducing membrane shaping.
• This work provides a synthetic platform for studying cytoskeletal mechanics and membrane-cell interactions.