Determining the Sequence Dependency of Self-Assembly of Elastin-Like Peptides Using Short Peptide Analogues with Shuffled Repetitive Sequences

Synthetic elastin-like peptides (ELPs) that possess characteristictropoelastin-derived hydrophobic repetitive sequences, such as (VPGVG)( n ), exhibit thermoresponsive reversible self-assembly.Although their thermoresponsive properties have been well-studied,the sequence-dependent and structural requirements for self-assemblyremain ambiguous. In particular, it is still unclear whether the aminoacid sequences derived from tropoelastin are necessary for self-assembly.In this study, 11 sequence-shuffled ELP analogues based on (FPGVG)(5), which is a previously developed short ELP (sELP), were designedto elucidate the sequence-dependent and structural requirements fortheir self-assembly. Among them, eight shuffled peptides exhibitedself-assembling properties, whereas the other three peptides weredifficult to dissolve in water. Structural analyses revealed thatthe structural characteristics of the three insoluble peptides weredifferent from those of their thermoresponsive analogues. Furthermore,the secondary structures of the peptide analogues possessing the self-assemblyabilities were different from each other. These results suggest thatthe potential for self-assembly and water solubility of sELPs dependon the primary structure in each repeated unit. Moreover, severalshuffled analogues exhibited more potent self-assembling propertiesthan the original (FPGVG)(5), indicating that shorter ELPscan be obtained using their novel motifs as repetitive units. We alsoobserved that the presence of Pro-Gly sequence in the repeating unitswas advantageous in terms of peptide solubility. Although furtheranalysis will be necessary to elucidate the molecular mechanism underlyingthe self-assembly of these sELPs, this study provides insights intothe relationship between the amino acid sequence and the self-assemblingability of the peptides for developing new sELPs for various applications.