[Relation between the lysozyme hydration isotherm and molecule packing in the solid phase]

Area of Science:

• Biophysics
• Materials Science

Context:

• Accurate measurement of mass changes in protein crystals is crucial for understanding hydration dynamics.
• Glutaraldehyde treatment is a common method for protein crystal stabilization.

Purpose:

• To present a novel micromethod for measuring mass changes in glutaraldehyde-treated protein crystals.
• To investigate the hydration properties of hen egg-white lysozyme across different crystal forms and amorphous films.

Summary:

• A cantilevered tungsten micro-needle system was developed for precise mass change measurements (0.1% accuracy) of protein crystals.
• Absorption isotherms for water uptake were determined for triclinic, monoclinic, and tetragonal lysozyme crystals, as well as amorphous films.
• Results indicate that lysozyme hydration is highly dependent on molecular packing, affecting water uptake at various relative humidities.

Impact:

• Provides a sensitive tool for studying protein crystal hydration and stability.
• Offers insights into the relationship between molecular arrangement and water interaction in proteins.
• Contributes to a better understanding of protein behavior in different physical states.