Self-Assembly of Minimal Peptoid Sequences.

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biomimetic Chemistry

Background:

• Peptoids are peptidomimetics with N-substituted glycine backbones, offering alternatives to peptide structures.
• Self-assembly of water-soluble minimal sequences is crucial for biomaterial compatibility and synthesis.
• Understanding peptoid self-assembly expands the scope of sequence-specific macromolecules.

Purpose of the Study:

• To investigate the self-assembly of trimeric, water-soluble alpha-peptoids.
• To characterize the morphology and aggregation behavior of these peptoid sequences.
• To explore the potential of peptoids as building blocks for novel nanomaterials.

Main Methods:

• Cryo-electron microscopy (Cryo-EM) for morphological analysis.
• Angle-resolved dynamic light scattering (DLS) for size and aggregation studies.
• Absorbance and fluorescence spectroscopy to probe molecular environments.

Main Results:

• Trimeric alpha-peptoids self-assembled with a low critical aggregation concentration (CAC ~ 0.3 wt %).
• Sequence-dependent morphologies were observed, including uniform nanofibers (~6 nm width), sheets, and globular clusters.
• Spectroscopic data revealed unique phenyl environments within the ordered nanofibers, suggesting pi-interactions.

Conclusions:

• Peptoid assembly occurs in a fully ionized state, distinct from amyloid-type peptide nanostructures.
• These findings demonstrate the versatility of peptoids in forming diverse, water-soluble nanostructures.
• The study expands the potential applications of sequence-specific bio- and biomimetic macromolecules.