Surface-Enhanced Raman Scattering for Direct Protein Function Investigation: Controlled Immobilization and...

Area of Science:

• Biophysical Chemistry
• Spectroscopy
• Biotechnology

Background:

• Surface-enhanced Raman spectroscopy (SERS) shows promise for protein analysis.
• Current limitations include poor spectral reproducibility due to random protein immobilization.
• Label-free probing of protein functions using SERS remains challenging.

Purpose of the Study:

• To develop SERS substrates with controlled protein immobilization for enhanced reproducibility.
• To investigate protein-ligand interactions using label-free SERS.
• To establish a platform for studying protein functional versatility.

Main Methods:

• Preparation of iminodiacetic acid (IDA)-functionalized silver substrates.
• Capture of His-tagged proteins via nickel-imidazole coordination for controlled immobilization.
• Analysis of protein-ligand interactions using SERS.

Main Results:

• Achieved excellent SERS spectral reproducibility with 6 polypeptides.
• Demonstrated successful label-free investigation of interactions between model proteins (Erv1C, AFP) and their ligands (Cyt c, ATRA).
• Validated the effectiveness of IDA-functionalized substrates for controlled protein immobilization.

Conclusions:

• IDA-functionalized silver substrates enable reproducible, label-free SERS analysis of proteins.
• This approach facilitates the study of protein-ligand interactions.
• The method holds potential for drug design and biotechnology applications.