Glycine Substitution Effects on the Supramolecular Morphology and Rigidity of Cell‐Adhesive Amphiphilic Peptides

• Published in: Chemistry : a European journal Vol. 25; no. 59; pp. 13523 - 13530
• Main Authors: Ishida, Atsuya, Watanabe, Go, Oshikawa, Mio, Ajioka, Itsuki, Muraoka, Takahiro
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 22.10.2019
• Subjects: Adhesives - chemistry; amphiphiles; Cell adhesion; Chemistry; Cytology; Gelation; gels; Glycine; Glycine - chemistry; Glycine Agents - chemistry; Glycine Agents - metabolism; Hydrogels; Hydrogels - chemistry; Mechanical properties; Molecular dynamics; Molecular Dynamics Simulation; Morphology; Nanofibers; Nanofibers - chemistry; Peptides; Peptides - chemistry; Protein structure; Rheological properties; Rheology; Rigidity; self-assembly; Sol-gel processes; Stiffness; Substitutes; amphiphiles; self-assembly; peptides; molecular dynamics; gels
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201902083

Self‐assembling peptides that are capable of adopting β‐sheet structures can generate nanofibers that lead to hydrogel formation. Herein, to tune the supramolecular morphologies, mechanical properties, and stimuli responses of the hydrogels, we investigated glycine substitution in a β‐sheet‐forming amphiphilic peptide. Glycine substitution generally enhances conformational flexibility. Indeed, glycine substitution in an amphiphilic peptide weakened the hydrogels or even inhibited the gelation. However, unexpectedly, glycine substitution at the center of the peptide molecule significantly enhanced the hydrogel stiffness. The central glycine substitution affected the molecular packing and led to twisted β‐sheet structures and to nanofiber bundling, which likely led to the stiffened hydrogel. Importantly, the supramolecular structures were accurately predicted by molecular dynamics simulations, demonstrating the helpfulness of these techniques for the identification of self‐assembling peptides. The hydrogel formed by the amphiphilic peptide with the central glycine substitution had cell adhesive function, and showed a reversible thermal gel‐to‐sol transition. Thus, glycine substitution is effective in modulating self‐assembling structures, rheological properties, and dynamics of biofunctional self‐assembling peptides. Bring on the substitute: Glycine substitution in a self‐assembling bioactive peptide affects the higher‐order structure and leads to the formation of bundled supramolecular nanofibers, enhances the stiffness of the hydrogel, and endows the system with a thermal response that shows a reversible gel‐to‐sol transition (see figure).