Small globular protein motif forms particulate hydrogel under various pH conditions

Area of Science:

• Biomaterials Science
• Protein Engineering
• Biophysics

Background:

• Biocompatible hydrogels are crucial for biomedical and biotechnological applications.
• Understanding protein self-assembly is key to developing novel biomaterials.

Purpose of the Study:

• To report a novel, small, naturally occurring protein motif capable of forming hydrogels.
• To investigate the mechanism of hydrogel formation by this protein motif.

Main Methods:

• Characterization of the protein motif YajC-CT from Escherichia coli.
• Thermal induction and concentration-dependent hydrogel formation studies.
• Atomic force microscopy (AFM) to analyze fibril structure.

Main Results:

• A protein motif, YajC-CT, formed transparent hydrogels at 90 °C at low concentrations (0.4 mg/mL).
• AFM revealed the formation of β-sheet-rich fibrils (2-3 nm height, micrometers length) from homogeneous particles.
• A three-step gelation pathway for YajC-CT was proposed, with pH-dependent fibril structure variations.

Conclusions:

• YajC-CT represents the smallest characterized globular protein module forming hydrogels.
• This protein motif serves as a valuable model for studying protein fibrillation and gelation mechanisms.
• Potential applications in biomaterials and biotechnology.