In nature, the switching of two adjacent amino acids usually leads to the protein fold differently, thus affecting their biological functions. Previous studies mainly focus on the sequence effect of the hydrophilic amino acids, while the effect of the hydrophobic amino acids alternation has not been extensively investigated. Therefore, we report here the effect of the V position in the hydrophobic region on the self-assembly behavior of the four isomers with the same composition but different hydrophobic amino acid sequence. The results demonstrated that the shift of V residue from C-terminal to N-terminal had a great effect on the final self-assembling morphologies, monolayer nanotubes were dominant structures for Ac-KIIIVK-NH2 (KIIIVK) and Ac-KIIVIK-NH2 (KIIVIK). In contrast, Ac-KIVIIK-NH2 (KIVIIK) and Ac-KVIIIK-NH2 (KVIIIK) self-assembled into bilayer twist ribbons and monolayer helical ribbons, respectively. Furthermore, we found that the lateral association of β-sheets can be greatly promoted when the V residue was embedded between I residues. The results clearly demonstrated the significant role of the hydrophobic amino acids sequence in determining the final self-assembling nanostructures, providing a simple and effective way for the construction of self-assemblies with varied morphologies and functions.
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