Defect-assisted protein HP35 denaturation on graphene

Area of Science:

• Materials Science
• Biophysics
• Nanotechnology

Background:

• Structural defects in nanomaterials critically influence their physical and chemical properties.
• Understanding how these defects affect biological interactions is crucial for nanomaterial safety and application.

Purpose of the Study:

• To investigate the impact of structural defects in graphene nanosheets on protein denaturation using molecular dynamics simulations.
• To elucidate the mechanisms underlying the enhanced biological toxicity of defective graphene.

Main Methods:

• Molecular dynamics simulations were employed to model the interaction between graphene nanosheets (ideal and defective) and a model protein (chicken villin headpiece subdomain, HP35).
• Defects on graphene were modeled using carboxyl groups to represent their anchoring effect.

Main Results:

• Defective graphene induced severe protein denaturation, while ideal graphene did not affect protein structure.
• Defect sites on graphene acted as anchors, attracting protein residues and initiating unfolding.
• Strong π-π stacking and hydrophobic interactions between protein core residues and defective graphene led to protein unfolding.

Conclusions:

• Structural defects in graphene significantly enhance its toxicity by promoting protein denaturation.
• Defect engineering offers a method to tune the biological properties and potential applications of nanomaterials.
• This study underscores the importance of considering defects in nanomaterial design for biological applications.