Structural investigation of Amphibalanus amphitrite cement proteins: an in silico study

Abstract

Balanomorpha, commonly known as barnacles, are leading biofouling animals belonging to subclass Cirripedia that adhere durably to different submerged surfaces by utilizing a chiefly proteinaceous cement. According to prior experiments, adhesion is most likely made possible by the self-assembling aggregates reputed as amyloid-like nanofibers. The secreted cement contains numerous proteins, among which CP19k and CP20k are thought to have a substantial influence on the adhesion process. The molecular configuration and atomistic interactions that result in this firm cement are not yet completely understood. Herein, artificial-intelligence-based structure prediction and molecular dockings were used to inspect the potential role of the AaCP19k and AaCP20k-1 of Amphibalanus amphitrite in the formation of amyloid-like nanofibers. The anticipated structure of AaCP19k was highly accurate, and its β-sandwich folding had a close resemblance to cross-β motifs found in amyloid nanofibers. In AaCP19k, β1–2 and β7–8 act as oligomerization sites where stable dimers and trimers can be assembled. These modeled oligomerization interfaces point to the self-assembly site through which fibrillization might happen. The structural flexibility of AaCP20k-1 yielded low-accuracy models, but a conserved β-hairpin and an α-helix were evident with high confidence. These structural properties can be employed in prospective studies to develop bioadhesives and design antifouling substances.