Peptide nucleic acids (PNAs) are high-affinity synthetic nucleic acid analogs capable of hybridization with native nucleic acids. PNAs synthesized having amino acid sidechains installed at the γ-position along the backbone provide a template for a single biopolymer to simultaneously encode nucleic acid and amino acid sequences. Previously, we reported the development of “bilingual” PNAs through the synthesis of an amphiphilic sequence featuring separate blocks of hydrophobic and hydrophilic amino acid functional groups. These PNAs combined the sequence-specific binding activity of nucleic acids with the structural organization properties of peptides. Like other amphiphilic compounds, these γ-PNAs were observed to assemble spontaneously into micelle-like nanostructures in aqueous solutions and disassembly was induced through hybridization to a complementary sequence. Here, we explore whether assembly of these bilingual PNAs is possible by harnessing the nucleic acid code. Specifically, we designed an amphiphile-masking duplex system in which spontaneous amphiphile assembly is prevented through hybridization to a nucleic acid masking sequence. We show that the amphiphile is displaced upon introduction of a releasing sequence complementary to the masking sequence through toehold mediated displacement. Upon release, we observe that the amphiphile proceeds to assemble in a fashion consistent with our previously reported structures. Our approach represents a novel method for controlled stimuli-responsive assembly of PNA-based nanostructures.
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Carbodiimide‐Fueled Assembly of π‐Conjugated Peptides Regulated by Electrostatic Interactions**
Peptides naturally have stimuli‐adaptive structural conformations that are advantageous for endowing synthetic materials with dynamic functionalities. Here, we report a carbodiimide‐based approach, combined with electrostatic modulation, to instruct π‐conjugated peptides to self‐assemble and be responsive to thermal disassembly cues upon consumption of the assembly trigger. Quaterthiophene‐functionalized peptides are utilized as a model system herein to study the formation of nanostructures at non‐equilibrium states. Peptides were designed to have aspartic acid at the termini to allow intramolecular anhydride formation upon adding carbodiimide, which consequentially reduces the electrostatic repulsion and facilitates assembly. We show that the carbodiimide‐fueled assembly and subsequent thermally assisted disassembly can be modulated by the net charge of the peptidic monomers, suggesting an assembly mechanism that can be encoded by sequence design. This carbodiimide‐based approach for the assembly of designer π‐conjugated systems offers a unique opportunity to develop bioelectronic supramolecular materials with controllable formation of dynamic and stimuli‐responsive structures.
more » « less- NSF-PAR ID:
- 10418721
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemSystemsChem
- Volume:
- 5
- Issue:
- 4
- ISSN:
- 2570-4206
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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