In Silicon Deciphering Atomic-Scale Structural Units in Peptide Glass

Area of Science:

• Materials Science
• Biophysics
• Chemical Physics

Background:

• Peptide glasses are promising biofunctional amorphous materials.
• Their atomic-level structure and organization remain poorly understood.
• Understanding this structure is crucial for designing novel glassy materials.

Purpose of the Study:

• To resolve the three-dimensional (3D) atomic-level structure of peptide glasses.
• To identify defining hallmarks of the glassy state in peptides.
• To establish a framework for designing functional amorphous peptide materials.

Main Methods:

• Utilized molecular dynamics simulations.
• Employed 2D solid-state Nuclear Magnetic Resonance (NMR) fingerprinting.
• Analyzed a cyclic dipeptide model system.

Main Results:

• Quantified pronounced conformational heterogeneity, distinguishing glasses from crystals.
• Observed reorganization of diverse H-bonding types, dependent on annealing rate.
• Identified dominance of non-hydrogen-bonded contacts, dependent on annealing temperature.
• Revealed molecular clusters with branched H-bonding topology that reproduce bulk properties.

Conclusions:

• Established a representative structural unit for amorphous peptide glasses, analogous to crystalline unit cells.
• Developed a framework to identify structural organization in peptide glasses with varying thermal histories.
• Paved the way for rational design of functional small-molecule glassy materials.