Principles Governing the Self-Assembly of Coiled-Coil Protein Nanoparticles.

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Self-assembly is the spontaneous organization of molecules into ordered structures, observed in viral capsid formation.
• Biological systems often utilize symmetry principles for efficient macromolecular assembly.
• Self-assembling protein nanoparticles (SAPNs) are engineered systems mimicking viral assembly for potential applications.

Purpose of the Study:

• To characterize the self-assembly process and resulting morphology of a novel SAPN system.
• To investigate the role of designed oligomerization domains (pentameric and trimeric) in guiding nanoparticle formation.
• To develop a mathematical framework for describing SAPN geometries and symmetries.

Main Methods:

• Utilized scanning transmission electron microscopy (STEM) to visualize nanoparticle structure.
• Employed small-angle neutron scattering (SANS) to analyze nanoparticle assembly and morphology.
• Developed and applied a mathematical toolkit for characterizing nanoparticle symmetry and architecture.

Main Results:

• The SAPN system predominantly forms a spherical core-shell morphology.
• Particles exhibit local and global symmetry axes of order 3 and 5, consistent with design principles.
• Schematics detailing the precise arrangement of protein chains within symmetric SAPNs were generated.

Conclusions:

• The designed SAPN system successfully self-assembles into ordered nanoparticles with predictable symmetries.
• The developed mathematical toolkit provides a powerful method for characterizing nanoparticle geometry.
• These findings offer insights into controlling nanoscale structures for future applications in medicine and materials science.