Peptide-Based Nanotubes

Abstract

AbstractAmphiphilic peptides, i.e., the peptides that possess lipophilic as well as hydrophilic properties, can be divided into two classes in terms of the structural elements. The first class is associated with genuine peptide molecules, in which rationally designed sequences of naturally occurring, hydrophobic and hydrophilic amino acid residues can furnish the amphiphilicity. These amphiphilic peptides are termed amphiphilic peptides (APs). Meanwhile, peptide amphiphiles (PAs) are defined as peptide derivatives, in which hydrophobic long chains are covalently connected to a hydrophilic peptide sequence. This chapter addresses the self-assembly behavior of the APs and PAs, focusing on the relationship between the secondary structure and resultant self-assembled structures. First, the author introduces the self-assembly of peptide nanotubes from the peptide NH2–Ala–Ala–Lys–Leu–Val–Phe–Phe–COOH. Next, the self-assembly of drug amphiphile carrying an anticancer drug into nanotube structures is discussed in terms of the structures of the building block. Self-assembled nanotubes from a various kind of peptide building blocks, e.g., peptide–dendron hybrid, dilysine peptide, amphiphilic block peptide, and amphiphilic peptoid oligomer, are introduced in terms of formation mechanism. The author also discusses diglycine and triglycine-based nanotubes, focusing on the stabilization by three-dimensional polyglycine II-type hydrogen bond networks. Finally, the nanotube self-assembly from functional linear PAs is also described.KeywordAmphiphilic peptidePeptide amphiphilePeptide nanotubeAmyloid β peptideDrug amphiphileAmphiphilic block peptideAmphiphilic peptoidPolyglycine II-type hydrogen bond