Post-Assembly Functionalization of Supramolecular Nanostructures with Bioactive Peptides and Fluorescent Proteins by Native Chemical Ligation

Abstract

Post-assembly functionalization of supramolecular nanostructures has the potential to expand the range of their applications. We report here the use of the chemoselective native chemical ligation (NCL) reaction to functionalize self-assembled peptide amphiphile (PA) nanofibers. This strategy can be used to incorporate specific bioactivity on the nanofibers, and as a model, we demonstrate functionalization with the RGDS peptide following self-assembly. Incorporation of bioactivity is verified by the observation of characteristic changes in fibroblast morphology following NCL-mediated attachment of the signal to PA nanofibers. The NCL reaction does not alter the PA nanofiber morphology, and biotinylated RGDS peptide was found to be accessible on the nanofiber surface after ligation for binding with streptavidin-conjugated gold nanoparticles. In order to show that this strategy is not limited to short peptides, we utilized NCL to conjugate yellow fluorescent protein and/or cyan fluorescent protein to self-assembled PA nanofibers. Förster resonance energy transfer and fluorescence anisotropy measurements are consistent with the immobilization of the protein on the PA nanofibers. The change in electrophoretic mobility of the protein upon conjugation with PA molecules confirmed the formation of a covalent linkage. NCL-mediated attachment of bioactive peptides and proteins to self-assembled PA nanofibers allows the independent control of self-assembly and bioactivity while retaining the biodegradable peptide structure of the PA molecule and thus can be useful in tailoring design of biomaterials.

Peptide Conjugation to a Polymer Coating via Native Chemical Ligation of Azlactones for Cell Culture

“…Similar intermediates that are formed during native chemical ligation processes have been exploited for the synthesis of complex peptides, macromolecules and hydrogels. 22,31,32 Native chemical ligation is a well-known and useful tool, although no such rearrangements have been previously reported with azlactone groups. Typically, native chemical ligation is reported to occur in aqueous conditions between pH 7 and 8 at room temperature.…”

Modular supramolecular ureidopyrimidinone polymer carriers for intracellular delivery

“…[6][7][8][9] Some examples of supramolecular polymers include materials based on discotic benzene tricarboxamides, 10 porphyrins, 11 carbohydrate conjugated aromatics, 12 and peptide amphiphiles. 13 However, few examples exist on the use of 1D supramolecular polymers for use in intracellular delivery, [14][15][16] while they can serve as a potentially attractive platform. A frequently reported supramolecular building block that proved to be suitable as biomaterial is the ureidopyrimidinone (UPy) unit, 17 that can dimerize via a self-complementary quadruple hydrogen bonding motif.…”

Biopolymers and supramolecular polymers as biomaterials for biomedical applications

“…This homeostasis allows the tissue to change the composition of the ECM when necessary, for instance, in the case of wound healing or development. Although some supramolecular-polymer-based materials have been developed to mimic the native ECM dynamics, 136,137 this feature remains a challenge. For instance, Sur et al bioactivated a supramolecular polymer with an RGDS cue using a photocleavable linker, Figure 5c.…”