Estimating Constraints for Protection Factors from HDX-MS Data.

Area of Science:

• Biochemistry
• Structural Biology
• Analytical Chemistry

Background:

• Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is valuable for protein structure and dynamics.
• Extracting amide hydrogen exchange rates from peptide mass changes is challenging.
• Current methods often lack residue-level resolution.

Purpose of the Study:

• To develop a method for extracting amide hydrogen exchange rates from time-resolved HDX-MS data.
• To address the non-uniqueness of solutions in HDX-MS data analysis.
• To provide constraints on protein protection factors and guide experimental design.

Main Methods:

• Utilizing time-resolved HDX-MS measurements on overlapping peptides covering the entire protein sequence.
• Applying a statistical clustering method to analyze and reduce multiple potential solutions for exchange rates.
• Calculating amide hydrogen exchange rate constants and protection factors.

Main Results:

• Demonstrated that overlapping peptide data enables extraction of amide hydrogen exchange rates.
• Showcased that solutions are often non-unique, requiring statistical analysis.
• Developed a method to cluster solutions, reducing ambiguity and providing meaningful constraints.

Conclusions:

• The statistical method effectively extracts protein protection factors from HDX-MS data.
• This approach offers valuable insights even when highly refined experimental data is impractical.
• It provides a systematic strategy for improving data collection for residue-level structural assessments.