Probing serpin conformational change using mass spectrometry and related methods

Area of Science:

• Biochemistry
• Structural Biology
• Biophysics

Background:

• Serpins (serine protease inhibitors) exhibit complex folding and misfolding mechanisms tied to thermodynamic metastability and conformational flexibility.
• Studying serpin stability and flexibility in solution is difficult due to their large size and tendency to aggregate.

Purpose of the Study:

• To review structural mass spectrometry techniques for analyzing serpin solution structures.
• To describe the application of hydrogen/deuterium exchange and chemical footprinting to serpin stability and flexibility.
• To discuss the use of these methods in understanding serpin polymerization.

Main Methods:

• Hydrogen/deuterium exchange mass spectrometry (HDX-MS) probes protein backbone dynamics and solvent accessibility.
• Chemical footprinting identifies regions of proteins protected from chemical modification.
• Ion mobility mass spectrometry (IM-MS) separates ions based on their size, shape, and charge.

Main Results:

• HDX-MS and chemical footprinting provide insights into serpin conformational flexibility and stability in solution.
• These techniques can characterize structural changes associated with serpin function and dysfunction.
• HDX-MS and IM-MS are valuable for investigating serpin polymerization and the structure of resulting polymers.

Conclusions:

• Structural mass spectrometry techniques are powerful tools for overcoming challenges in studying large, aggregation-prone proteins like serpins.
• These methods enable detailed characterization of serpin conformational dynamics, stability, and polymerization mechanisms in solution.
• The reviewed techniques offer a comprehensive approach to understanding serpin structure-function relationships.