Intriguingly, 13-mer frog-peptide, temporin L (TempL) contains 50% aromatic residues within its first eight residues.Considering the role of aromatic residues in self-assembly of peptides and the potential of such peptides in biomedical applications, we envisaged to identify new short self-assembling peptides from the amino-terminus of TempL and characterize their structural and biological properties.Thus, starting from the 8 th to the 1 st residue of TempL, we synthesized, five 4-8 residue peptides (T-4mer to T-8mer).Different ultrastructural studies suggested nano-J o u r n a l P r e -p r o o f spherical/nano-fibrillar structures of these peptides.Remarkably, T-6mer, T-7mer and T-8mer exhibited polyproline type-II CD spectra of collagen-like triple-helical structure and sigmoidal melting curves like that we observed with rat-tail type-I collagen.Amazingly, the T-8mer peptide at 1.5% (w/v) forms hydrogel within an hour indicating its ability to form supramolecular assembly, saturated with water.We further studied collagen-mimetic nature of these TempL-derived peptides.HepG2 cells showed significant adhesions onto the coatings of T-6mer, T-7mer, T-8mer peptides and rat-tail type-I collagen which got compromised when these cells were pre-treated with antibody of collagen receptor, integrin 21.Interestingly, following the adhesions onto the surface of these TempL-derived peptides, cytoskeletal organization was induced in HepG2 cells like that observed in the presence of a collagen protein.Overall, the current results demonstrated the dissection of a frog-peptide, TempL with revelation of collagenmimetic peptides from its aromatic-residue rich amino-terminus.
Verma et al. (Sun,) studied this question.