Which spectroscopic technique helps in determining both primary and secondary structure of proteins?

Infrared spectroscopy is a powerful technique for elucidating both the primary and secondary structures of proteins. This method operates based on the absorption of infrared radiation by molecular vibrations within a sample, including bending and stretching of covalent bonds.

In terms of primary structure, infrared spectroscopy can provide information about specific functional groups and peptide linkages within the protein. The distinctive absorption peaks can indicate the presence of particular amino acid side chains, allowing researchers to infer the sequence of the peptide chain.

Regarding secondary structure, infrared spectroscopy is particularly adept at identifying the characteristic amide I and amide II bands, which correspond to the backbone C=O and C-N stretching vibrations within the peptide bonds. These bands can reveal information about the protein's folding patterns, such as alpha-helices and beta-sheets, because different secondary structures have unique infrared absorption characteristics.

In contrast, the other techniques listed are not primarily focused on determining both aspects of protein structure. Mass spectrometry is mainly used for analyzing molecular weight and identifying peptides but does not provide direct structural information. Dynamic light scattering primarily informs about particle size and distribution, not structural details. Gas chromatography is used for separating volatile compounds and is not suitable for analyzing the structure of proteins, which are generally not volatile. Thus, infrared