Background: Peptide self-assembly is a key phenomenon in molecular science, underpinning advancements in regenerative medicine, biosensing, and nanotechnology. While natural peptides offer biocompatibility, they are limited by low structural diversity, biological instability, and inconsistent self-assembly behavior. Peptides composed of non-natural amino acids, such as fluorinated β-diarylamino acids, offer a promising route to overcome these limitations and engineer next-generation biomaterials with enhanced functional properties.
Objective: To investigate how stereochemistry and environmental factors influence the conformational dynamics and aggregation behavior of non-natural tetrapeptides containing fluorinated β-diarylamino acids and L-alanine.
Methods: We performed classical molecular dynamics (cMD) and accelerated molecular dynamics (aMD) simulations using the Amber software suite with the ff19SB force field in explicit TIP3P water. Four stereo chemically distinct tetrapeptides were studied at concentrations of 681 μM (9 copies) and 1860 μM (30 copies) over 2.8 μs (cMD) and 0.3 μs (aMD) of cumulative simulation time. Structural analyses focused on secondary structure motifs, compactness, flexibility, hydrogen bonding networks, and solvent-accessible surface area (SASA).
Results: Aggregation propensity was highly dependent on peptide stereochemistry and concentration. Turn motifs were predominant across all peptides, with variations in hydrogen bonding and structural compactness. aMD simulations revealed deeper aggregation states with up to 27.5 intermolecular hydrogen bonds and significantly reduced SASA values. D1Cl1 consistently showed strong aggregation due to a rigid β-turn geometry and stable π–π interactions, while D2Cl2 displayed prominent clustering under aMD, linked to its stereochemical configuration.
Conclusion: Our findings demonstrate that stereochemical design and simulation strategy critically influence peptide self-assembly. The integration of non-natural amino acids enables the formation of stable supramolecular aggregates with desirable properties, providing a rational framework for the design of advanced peptide-based biomaterials for therapeutic and technological applications.