Interactions between Oligoethylene Glycol-Capped AuNPs and Attached Peptides Control Peptide Structure
Logan M Wilder1, Paul R Handali1, Lauren J Webb1
1Department of Chemistry and Texas Materials Institute, The University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States.
Bioconjugate Chemistry
|September 24, 2020
Summary
Attaching peptides to gold nanoparticles (AuNPs) using click chemistry induces a structural change from random coil to alpha-helix. The nanoparticle
Area of Science:
- Nanotechnology
- Biomaterials Science
- Chemical Biology
Background:
- Peptide structure is crucial for the function of peptide-functionalized nanoparticles.
- Oligoethylene glycol (OEG) ligands are used to passivate gold nanoparticles (AuNPs).
Purpose of the Study:
- To investigate the covalent attachment of model peptides to OEG-capped AuNPs.
- To determine the structural changes of peptides upon attachment to AuNPs.
- To explore the influence of the nanoparticle surface on peptide structure.
Main Methods:
- Cu+-catalyzed azide-alkyne cycloaddition for peptide conjugation.
- Fourier-transform infrared (FTIR) spectroscopy to confirm peptide attachment.
- Amino acid analysis to quantify peptide density.
- Circular dichroism (CD) spectroscopy to assess peptide secondary structure.
Main Results:
- Peptides were successfully attached to OEG-capped AuNPs.
- Approximately 3-4 peptides were immobilized per AuNP.
- Peptides transitioned from a random coil to an alpha-helical structure upon conjugation.
- The capping layer significantly influenced peptide structure.
- AuNP-peptide conjugates exhibited water solubility.
- Helical peptides were oriented tangent to the AuNP surface.
Conclusions:
- The surface of gold nanoparticles can induce significant structural changes in attached peptides.
- OEG-capped AuNPs provide a versatile platform for creating peptide-nanoparticle conjugates with controlled structure.
- The orientation of peptides on the nanoparticle surface has implications for biorecognition applications.
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