Self-Assembly of Surfactant-like Peptides

Abstract

Inspired by recent work describing surfactant-like peptides, we have carried out a systematic study on peptides with the underlying composition of V6D2, altering the absolute sequence to determine the importance of the surfactant-like structure. All of the peptides examined here formed self-assembled structures in water. However, in contrast to other reports, we have found a surprising diversity of structures including fibers, tapes, and twisted ribbons but an absence of the vesicles and nanotubes described previously. Further investigations demonstrated that peptide purity plays a significant role in the outcome of the self-assembly. Different batches behave very differently, which can be linked to the compositions of these batches. This work shows that there is a need for not only rational design but also ease of synthesis of the building blocks for self-assembled structures.

Enzymatically activated emulsions stabilised by interfacial nanofibre networks

“…[15][16][17][18] A number of chemical and physical means have been used as a trigger to initiate self-assembly and to influence the produced nanostructures. [19][20][21][22][23][24] In particular, the biocatalytically triggered self-assembly of aromatic peptide amphiphiles enables control of the self-assembly process under constant and physiological conditions. 25 Xu et al was the first to exploit enzymatic self-assembly of Fmoc-amino acid using an alkaline phosphatase to dephosphorylate Fmoc-tyrosine phosphate (Fmoc-Yp) under basic conditions, forming a hydrogel, 26 but many more followed.…”

Self-assembled Structures from Amphiphilic Peptides

“…The latter is predominantly occupied by charged and polar amino acids; these are: arginine (R), [6,7] histidine (H), [7,8] lysine (K), [9][10][11][12][13][14][15] aspartic acid (D), [16,17] glutamic acid (E), [11,18] serine (S), threonine (T), asparagine (N), glutamine (Q), and cysteine (C). [13] The design of the hydrophobic part is based on amino acids with neutral and nonpolar side-chains such as glycine (G), [16] alanine (A), [15,19] valine (V), [17,20] leucine (L), [9,17] isoleucine (I), [21] methionine (M), phenylalanine (F), [22,23] tyrosine (Y), and tryptophan (W). [7,[10][11][12][13][14]23] Depending on the hydrophobic to hydrophilic ratio and the sequence, various self-assembled structures can be constructed -as indicated in the associated references for the above amino acids -although the hydrophobicity is moderated by the polar character of the peptide's backbone.…”

Self assembly of a model amphiphilic phenylalanine peptide/polyethylene glycol block copolymer in aqueous solution

“…targeted binding to proteins) can potentially be combined with amphiphilic properties such as self-assembly into micelles to create novel materials with hybrid properties [3][4][5]. There are three broad classes of peptide amphiphilethose with hydrophilic peptides attached to hydrophobic chains [6][7][8][9][10][11], the inverse case of hydrophobic peptides attached to hydrophilic chains [12][13][14][15][16][17] and thirdly surfactant-like peptides comprising connected sequences of hydrophobic and hydrophilic amino acids [9,[18][19][20]. The former category mainly comprises peptides attached to alkyl chains of which dodecyl to octadecyl chains are of most interest in terms of amphiphilicity [11,21].…”

“…We have recently begun a programme to investigate the selfassembly of peptide amphiphiles comprising peptides based on a fragment of the amyloid beta peptide, Aβ (16)(17)(18)(19)(20), i.e. KLVFF, conjugated to PEG including peptide amphiphiles such as FFKLVFF-PEG (PEG M n = 3300).…”

“…KLVFF has been identified as a minimal key sequence in the formation of amyloid fibrils by the full Aβ peptide [22,23]. FFKLVFF contains the peptide sequence FFKLVFF, which is Aβ (16)(17)(18)(19)(20) extended by two phenylalanine residues. FFKLVFF is highly hydrophobic and does not dissolve in water (it does fibrillise in methanol [24]).…”