Structural adaptability and surface activity of peptides derived from tardigrade proteins

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Tardigrades exhibit remarkable desiccation tolerance.
• Tardigrade-specific cytoplasmic abundant heat soluble (CAHS) proteins are crucial for this protection.
• Understanding CAHS protein structure-function relationships is key to developing biomimetic materials.

Purpose of the Study:

• To synthesize and characterize model peptides based on conserved CAHS motifs.
• To investigate the desiccation-induced structural changes in these model peptides.
• To assess the potential of these peptides for biomimetic cryoprotective applications.

Main Methods:

• Circular dichroism spectroscopy
• Two-dimensional infrared spectroscopy
• Molecular dynamics simulations
• Sum-frequency generation spectroscopy
• Synthesis of model peptides from CAHS motifs

Main Results:

• Model CAHS peptides are largely disordered but adopt a more alpha-helical structure upon addition of 2,2,2-trifluoroethanol, mimicking desiccation.
• This behavior mirrors that of full-length CAHS proteins under desiccating conditions.
• All synthesized peptides demonstrated surface activity and helical structuring at the air/water interface, simulating partial desiccation.

Conclusions:

• The model peptides partially retain the desiccation-induced structural behavior of full-length CAHS proteins.
• Amino acid sequences with high helix-forming propensities may drive this structural adaptation.
• These findings provide a basis for designing novel synthetic peptide-based cryoprotective materials.