Methylated mono- and di(ethylene glycol)-functionalized beta-sheet forming polypeptides.

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Protein Conformation

Background:

• Development of synthetic polypeptides with controlled secondary structures is crucial for biomaterial applications.
• Functionalized amino acid-based polymers offer tunable properties for advanced materials.

Purpose of the Study:

• To synthesize and characterize novel methylated mono- and di(ethylene glycol)-functionalized polymers of L-serine and L-cysteine.
• To investigate the solution behavior and solid-state conformation of these new polypeptide materials.

Main Methods:

• Synthesis of functionalized amino acid-N-carboxyanhydrides.
• Transition metal-catalyzed ring-opening polymerization.
• Circular dichroism spectroscopy for conformational analysis.
• Solubility studies across varying pH and solvent conditions.

Main Results:

• Three polymers were synthesized: poly(O-(2-(2-methoxyethoxy)ethyl)-L-serine) (poly(1)), poly(O-(2-(methoxy)ethyl)-L-serine) (poly(2)), and poly(S-(2-(2-methoxyethoxy)ethoxy)carbonyl-L-cysteine) (poly(3)).
• Poly(1) demonstrated high water solubility, independent of pH.
• Poly(1) adopted a random coil conformation in water and trifluoroethanol, transitioning to a beta-sheet conformation upon addition of methanol or acetonitrile.

Conclusions:

• A new class of readily processable, beta-sheet-forming polypeptides has been developed.
• Poly(1) shows potential for applications requiring tunable secondary structure and good water solubility.
• The findings provide insights into the structure-property relationships of functionalized polypeptides.