Molecular dynamics analysis of a buckyball-antibody complex

Area of Science:

• Biophysics
• Nanotechnology
• Computational Chemistry

Background:

• Carbon nanoparticles, such as buckyballs (C60), are increasingly studied for biomedical applications.
• Understanding the molecular interactions between nanoparticles and biological molecules is crucial for their safe and effective use.

Purpose of the Study:

• To investigate the binding mechanisms between a carbon nanoparticle (C60) and an antibody using molecular dynamics simulations.
• To determine the affinity, specificity, and interaction modes involved in this bio-nano complex formation.

Main Methods:

• Multinanosecond molecular dynamics simulations were employed to model the interaction between C60 and an antibody.
• Analysis focused on desolvation, shape complementarity, side-chain interactions, and specific binding forces like hydrophobic, polar, and pi-stacking interactions.

Main Results:

• The antibody binding site effectively desolvated the C60 nanoparticle, with high shape complementarity and extensive side-chain interactions.
• Predominantly hydrophobic interactions drove binding, supplemented by significant polar interactions and abundant pi-stacking, including aromatic and ionic side chains.
• Approximately 17% of the C60 surface remained exposed, offering potential for functionalization.

Conclusions:

• Pi-stacking interactions are highly effective and common in the biological recognition of pi-electron-rich carbon nanoparticles.
• Standard protein binding sites, like those in antibodies, can achieve high-affinity and specific binding to carbon nanoparticles through established protein-ligand recognition modes.