Discontinuous Molecular Dynamics Captures Sequence-Induced Diversity of Barnacle Cement Peptide Adsorption and β-Sheet Assembly on a Polystyrene Surface

Marine biofouling, particularly barnacle adhesion, poses significant economic and environmental challenges. Understanding the molecular mechanisms of barnacle cement peptide (BCP) adsorption and self-assembly on surfaces is crucial for developing effective antifouling strategies. In this study, we employed discontinuous molecular dynamics (DMD) simulations to investigate the sequence-induced diversity in interfacial behavior among three BCP variants from the cp19k protein family: simBCP (simple domain), chgBCP (simple plus charged domain), and ranBCP (randomized sequence). Our simulation successfully captured the complete trajectories of adsorption and self-assembly on a model polystyrene surface, demonstrating the formation dynamics and structural details of the surface-bound β-sheets previously inaccessible to atomistic observation. The results reveal that simBCP readily forms stable intermolecular β-sheets upon surface adsorption, featuring a characteristic tandem binary pattern directly corresponds to identified Gly/Ser/Thr/Val/Ala-X motifs in adhesive proteins. Conversely, the native α-helical structure of chgBCP remained stable on the surface due to higher unfolding enthalpy from the charged domain and surface-induced constraints, forming only transient intramolecular β-hairpins, despite forming extended β-sheets in the bulk environment. ranBCP failed to form ordered structures, transitioning instead into random coils. The analysis also reveals that Phe, Val, and Ile residues exhibit the strongest surface affinity through π-π stacking and hydrophobic forces, suggesting their critical role in stabilizing BCP adsorption. By bridging the gap between macroscopic experimental observations and fundamental atomistic mechanisms, this work provides detailed molecular insights into barnacle adhesion and a strategic basis for developing eco-friendly antifouling coatings and high-performance adhesives.