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Engineered gold nanoparticles (AuNPs) have great potential in many applications due to their tunable optical properties, facile synthesis, and surface functionalization via thiol chemistry. When exposed to a biological environment, NPs are coated with a protein corona that can alter the NPs’ biological identity but can also affect the proteins’ structures and functions. Protein disulfide isomerase (PDI) is an abundant protein responsible for the disulfide formation and isomerization that contribute to overall cell redox homeostasis and signaling. Given that AuNPs are widely employed in nanomedicine and PDI plays a functional role in various diseases, the interactions between oxidized (oPDI) and reduced (rPDI) with 50 nm citrate-coated AuNPs (AuNPs) are examined in this study using various techniques. Upon incubation, PDI adsorbs to the AuNP surface, which leads to a reduction in its enzymatic activity despite limited changes in secondary structures. Partial enzymatic digestion followed by mass spectrometry analysis shows that orientation of PDI on the NP surface is dependent on both its oxidation state and the PDI:AuNP incubation ratios.
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This content will become publicly available on July 18, 2026
Cytochrome c Facilitates Binding between Lipid Bilayers and Citrate-Coated Gold Nanoparticles in Coarse-Grained Simulations
Characterization and prediction of the interactions between engineered nanoparticles (ENPs), proteins, and biological membranes is critical for advancing applications to nanomedicine and nanomanufacturing while mitigating nanotoxicological risks. In this work, we employ a coarse-grained dissipative particle dynamics (DPD) simulation to investigate the interactions among cytochrome c (CytC), lipid bilayers, and citrate-coated gold nanoparticles (AuNPs). We updated the DPD potential to accurately represent binding potentials between molecules, and validated the model relative to an all-atom representation. The DPD simulations successfully replicate experimental observations: CytC facilitates the binding of citrate-coated AuNPs to lipid bilayers composed of 90% dioleoylphosphatidylcholine (DOPC) mixed with 10% stearoylphosphatidylinositol (SAPI) or 10% tetraoleoyl cardiolipin (TOCL) but not to pure 100% DOPC bilayers. In addition, the simulations reveal nuanced differences in binding preferences between CytC, the lipid bilayers, and the ENP, at a scale that is not presently directly observable in experiments. Specifically, we found that the surface coating of the nanoparticles─viz variations in the CytC surface density─affects the protein-mediated binding with the bilayers. Such a molecular-sensitive result underscores the utility of DPD simulations in simulating complex biological systems.
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- Award ID(s):
- 2001611
- PAR ID:
- 10617054
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Journal of Chemical Theory and Computation
- ISSN:
- 1549-9618
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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