What is the primary purpose of infrared (IR) spectroscopy in studying proteins?

The primary purpose of infrared (IR) spectroscopy in studying proteins centers on analyzing the vibrational modes of protein bonds. This technique measures how molecules absorb infrared light, which causes different chemical bonds within the protein to vibrate at specific frequencies. Each type of bond and molecular structure exhibits distinct vibrational characteristics, allowing researchers to infer details about the protein's secondary structure—such as the presence of alpha-helices or beta-sheets—as well as the environment around specific functional groups.

By interpreting the infrared spectra, scientists can gather insights into protein conformation and interactions. For example, shifts in peak positions or intensities can indicate changes in hydrogen bonding or the formation of specific structures, making IR spectroscopy a valuable tool for understanding protein function and dynamics in a variety of contexts.

The other options focus on aspects not directly measured or analyzed through IR spectroscopy, making them less applicable in the context of protein study through this specific technique.