Raman Spectroscopy in Protein Analysis

Raman spectroscopy has emerged as a powerful tool for probing the molecular structure and dynamics of proteins in a label-free and non-destructive manner. By measuring inelastically scattered light from vibrational modes, it provides a detailed fingerprint of amino acid side chains, backbone conformations and secondary-structure elements. Advances in excitation strategies—such as resonance and ultraviolet-resonance Raman—have amplified signals from specific chromophores, enabling selective observation of heme groups, aromatic residues or prosthetic moieties. Surface-enhanced Raman scattering (SERS) further boosts sensitivity by many orders of magnitude through the use of metallic nanostructures, allowing detection down to single-molecule levels. Together with chemometric analysis, these approaches permit discrimination of protein conformers, monitoring of folding and misfolding events, and characterisation of post-translational modifications such as glycosylation and metal-ion binding. Recent improvements in time-resolved Raman have opened a window onto subpicosecond dynamics in photoactive proteins, while polarisation-resolved measurements afford new insights into orientation and local symmetry. These developments have broadened the applicability of Raman spectroscopy from fundamental folding studies to biomarker discovery, quality control of biotherapeutics and label-free imaging of proteins in cells and tissues.

Research from Nature Portfolio

In a seminal demonstration of spectral sorting, a Fourier polar representation method was applied to surface-enhanced Raman spectra of single amino-acid molecules and small biomolecular mixtures. This non-fitting strategy employs simple sine and cosine transforms to project each spectrum into a polar map, enabling rapid visual clustering without prior knowledge of classes. The approach was validated on cysteine monomers and a ternary mixture of odorous compounds, highlighting its potential for automated grouping of single-protein or peptide spectra in complex matrices. The graphical output facilitates direct comparison with conventional principal component analysis, offering complementary strengths in speed and interpretability. This work paves the way for real-time, high-throughput classification of protein samples in fields ranging from diagnostics to proteomics.

Raman Spectroscopy in Protein Analysis publication trend

The graph below shows the total number of articles in raman spectroscopy in protein analysis across all publications each year (not limited to Nature Index journals).

Technical terms

Raman spectroscopy: A vibrational spectroscopic technique that measures frequency shifts in scattered light to provide a fingerprint of molecular bonds and conformations.

Resonance Raman spectroscopy: A variant in which the excitation wavelength coincides with an electronic transition, selectively enhancing vibrations of chromophoric groups.

Surface-enhanced Raman scattering (SERS): An approach that uses metal nanostructures to amplify Raman signals by factors up to 10⁸–10¹⁰, enabling trace and single-molecule detection.

Polarized Raman spectroscopy: A method that analyses the orientation of molecular bonds by comparing scattering intensities with different polarisation configurations.

Chemometric analysis: Multivariate statistical techniques, including principal component analysis and partial least squares regression, used to extract meaningful patterns from complex spectral datasets.

References

1. Sorting of Single Biomolecules based on Fourier Polar Representation of Surface Enhanced Raman Spectra. Scientific Reports (2016).
2. Polarized resonance Raman measurements for accurate heme protein differentiation. Journal of Molecular Structure (2025).
3. Detection of glycosylation and iron-binding protein modifications using Raman spectroscopy. Analyst (2017).
4. Resonance Raman evidence for tyrosine involvement in the radical site of galactose oxidase. Journal of Biological Chemistry (1989).
5. Ultraviolet-resonance femtosecond stimulated Raman study of the initial events in photoreceptor chromophore. EPJ Web of Conferences (2013).