Hydrogen–deuterium exchange

Hydrogen–deuterium exchange

Schematic of the HDX-MS workflow

Hydrogen–deuterium exchange (HDX) is a chemical reaction in which the hydrogen atoms in a molecule are replaced by deuterium atoms. This process is particularly useful in the study of proteins and other biomolecules, as it provides insights into their structure and dynamics.

Mechanism

HDX occurs when a molecule containing hydrogen is exposed to deuterium, often in the form of heavy water (D_O). The exchange of hydrogen for deuterium can occur at various sites within the molecule, depending on the conditions such as pH, temperature, and the presence of catalysts. In proteins, the exchange typically occurs at the amide hydrogens in the peptide backbone.

Applications

HDX is widely used in mass spectrometry (MS) to study protein structure and dynamics. In HDX-MS, proteins are exposed to deuterium, and the rate of exchange is measured by mass spectrometry. This technique provides information about the conformation of proteins, their folding and unfolding processes, and their interactions with other molecules.

Protein Structure Analysis

HDX-MS is a powerful tool for analyzing the tertiary structure of proteins. By measuring the rate of hydrogen-deuterium exchange, researchers can infer which regions of a protein are more flexible or exposed to solvent, and which are more rigid or buried within the protein structure.

Protein-Protein Interactions

HDX-MS can also be used to study protein-protein interactions. When two proteins interact, the interface regions often become protected from exchange, allowing researchers to map the interaction sites.

Advantages and Limitations

HDX-MS offers several advantages, including the ability to study proteins in their native state and the provision of dynamic information about protein structure. However, it also has limitations, such as the requirement for specialized equipment and expertise, and the potential for back-exchange of deuterium to hydrogen during analysis.

Related pages

• Mass spectrometry
• Protein structure
• Isotope labeling