Self-sorting heterodimeric coiled coil peptides with defined and tuneable self-assembly properties

Abstract

Coiled coils with defined assembly properties and dissociation constants are highly attractive components in synthetic biology and for fabrication of peptide-based hybrid nanomaterials and nanostructures. Complex assemblies based on multiple different peptides typically require orthogonal peptides obtained by negative design. Negative design does not necessarily exclude formation of undesired species and may eventually compromise the stability of the desired coiled coils. This work describe a set of four promiscuous 28-residue de novo designed peptides that heterodimerize and fold into parallel coiled coils. The peptides are non-orthogonal and can form four different heterodimers albeit with large differences in affinities. The peptides display dissociation constants for dimerization spanning from the micromolar to the picomolar range. The significant differences in affinities for dimerization make the peptides prone to thermodynamic social self-sorting as shown by thermal unfolding and fluorescence experiments, and confirmed by simulations. The peptides self-sort with high fidelity to form the two coiled coils with the highest and lowest affinities for heterodimerization. The possibility to exploit self-sorting of mutually complementary peptides could hence be a viable approach to guide the assembly of higher order architectures and a powerful strategy for fabrication of dynamic and tuneable nanostructured materials.

Tailoring Supramolecular Peptide–Poly(ethylene glycol) Hydrogels by Coiled Coil Self-Assembly and Self-Sorting

“…The peptides EI, EV, KI and KV (Table 1, Figure 2) are random coils as monomers and designed to heterodimerize and fold into parallel coiled coils at neutral pH. 33 Complementary charged residues at the e and g position, either glutamic acid (Glu, E) or lysine (Lys, K), favor heterodimerization. In order to vary the affinity for dimerization EI and KI have mostly isoleucine (Ile, I) at position a, whereas EV and KV have valine (Val, V) at this position.…”

“…The large differences in affinities promotes thermodynamic self-sorting, which makes it possible to obtain defined stoichiometries of different heterodimers in complex mixtures of peptides and to dynamically exchange peptides in specific and already formed dimers. 33 To enable peptide conjugation to the maleimide functionalized 4-arm-PEG, an off-heptad cysteine (Cys, C) residue was included at the peptide C-terminal in EI and EV and at the Nterminal in KI and KV. The formation of the thioether bond upon conjugation and complete absence of unreacted maleimides were verified by 1 H-NMR ( Figure S1).…”

“…EI-, EV-, KI-and KV peptides with a terminal Cys were ordered and customsynthesized by GL Biochem Ltd and used as received, whereas peptides without a terminal Cys were synthesized in house as described previously. 33 Briefly, the in house synthesis was performed using a standard Fmoc protocol with HCTU as coupling agent. The peptides were purified by reverse phase HPLC and identified by MALDI-ToF spectroscopy with α-cyano-4-hydroxycinnamic acid as matrix.…”

“…33 The peptides are non-orthogonal and can form four different heterodimers that display large differences in affinities, which in turn promotes thermodynamic self-sorting. Here, we have conjugated these peptides to 4-armed star-shaped PEGs and investigated their assembly into supramolecular PEG-peptide networks and hydrogels ( Figure 1).…”

Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix–Loop–Helix Peptide Superstructures for Controlled Encapsulation and Release

“…pH, [14][15][16] temperature, 17,18 metal ion coordination, [19][20][21] and by specific interactions with complementary peptides or other biomolecules. [22][23][24] The numerous possibilities to modulate the assembly process have enabled development of a wide range of peptidebased materials for applications in biosensing, 25,26 drug delivery, 27,28 and tissue engineering. 29,30 Metal cations are attractive modulators of peptide-directed self-assembly since peptides can coordinate certain cations with high specificity and affinity.…”