Biocatalytic self-assembly of 2D peptide-based nanostructures

Abstract

Peptide based 2D nanostructures of micronscale size in both X and Y dimensions are extremely rare because amino acid chirality favours helical structures, and nucleation-growth mechanisms usually favour uni-directional growth. We demonstrate the production of extended two-dimensional (2D) peptide nanostructures via the thermolysin catalysed condensation of Fmoc protected hydrophilic amino acid (serine, Fmoc-S) and a hydrophobic amino acid ester (phenylalanine, F-OMe). We propose that lateral self-assembly is enabled by the reversible nature of the system, favouring the thermodynamic product (extended sheets) over kinetically favoured 1 dimensional structures. Fmoc-SF-OMe forms extended arrays of β-sheet structures interlock via π-stacking between Fmoc groups. We propose that, due to its alternating hydrophilic/hydrophobic amino acid sequence, amphiphilic sheets presenting either phenyl or hydroxyl functionality are formed that assemble pair-wise, thereby shielding hydrophobic groups from the aqueous environment. Formation of these structures was supported by fluorescence emission spectroscopy, FTIR and XRD analysis and molecular mechanics minimization. At enhanced enzyme concentrations, hierarchical self-assembly was observed giving rise to spherulitic structures, with the number of spherulites dictated by enzyme concentration

Construction of supramolecular hydrogels using photo-generated nitric oxide radicals

“…The observed twist in the filaments was attributed to H-bonding between the chiral gelator molecules, which imparts curvature into the growing one-dimensional filaments, suppressing the formation of twodimensional sheets. 11,29,30 Significantly, the AFM images revealed the presence of lefthanded helical nanofilaments rather than conventional righthanded helical filaments observed in previous studies involving FY (Fig. 2d).…”

Biocatalytic Self‐Assembly of Nanostructured Peptide Microparticles using Droplet Microfluidics

“…To demonstrate versatility of this approach, Fmoc‐T (Threonine) and L‐OMe (Leucine methyl ester), were used to form nanostructured gels by thermolysin catalyzed condensation ( Figure a). Biocatalytic condensation in high yield, and consequent self‐assembly of the Fmoc‐TL‐OMe peptides resulted in formation of nanostructured fibres, causing gelation, as previously demonstrated in bulk systems . In here, it was investigated whether this approach could be used to produce gel phase microparticles in the same microfluidic setup (Figure b).…”

Spatiotemporal control of the creation and immolation of peptide assemblies

“…Enzymatic condensation of amino acids, hydrolysis, and side chain-modification are the three typical ways to carry out enzyme-instructed self-assembly (EISA) [7,53,54],which has attracted extensive research interest in recent years ( Figure 2) [22,67]. Proteases that can catalyze the condensation of an amine and a carboxylic acid provide a route for in situ formation of self-assembled peptidic nanostructures from amino acid precursors [68,69]. When amino acids with aromatic side chains are introduced, supramolecular structures can be generated as a result of electronic modification of the aromatic substituents [70,71].…”