Hydrogen/Deuterium Exchange Mass Spectrometry (HDX-MS)

Vocabulary flashcards covering the components and findings of HDX-MS experiments as applied to prion proteins.

Hydrogen/Deuterium Exchange Mass Spectrometry (HDX-MS)

An experimental technique that measures the accessibility of backbone amide hydrogens to solvent to provide information on protein conformation, hydrogen bonding, and flexibility.

MS/MS (Tandem Mass Spectrometry)

A mass spectrometry technique in which peptide ions are first selected and then fragmented into smaller ions to identify amino acid sequences and determine regions containing deuterium.

Deuterium

A stable isotope of hydrogen that contains one proton and one neutron; used in HDX experiments to replace exchangeable hydrogens in proteins, causing a measurable increase in mass.

$$D_2O$$

Heavy water; the substance from which deuterium atoms are exchanged with hydrogen atoms in a protein during an HDX-MS experiment.

High-exchange regions

Protein regions that exchange more deuterium because they are generally more exposed or flexible.

Low-exchange regions

Protein regions that exchange less deuterium because they are more protected and structurally constrained.

$\beta1-H1-\beta2-H2$ region

The specific segment of the prion protein that undergoes significant structural rearrangement and changes in solvent protection during the conversion from $PrP^C$ to $PrP^\beta$.

$\beta1-H1-\beta2$ loop

The structural loop that moves away from the $H2-H3$ core during the conversion of $PrP^C$ into $PrP^\beta$.