Self-Assembly of a Barnacle Cement Protein (MrCP20) into Adhesive Nanofibrils with Concomitant Regulation of CaCO₃ Polymorphism

Barnacles are convenient model organisms to study both biomineralization and bioadhesion phenomena. They secrete a proteinaceous adhesive from cement proteins (CPs) strongly attach solid immersed substrates. More recently, it has been suggested that some CPs also play key role in regulating the calcification of barnacles’ protective shells. In this study, combining solution solid-state NMR spectroscopy, Raman infrared spectroscopy studies, atomic force microscopy (AFM) transmission electron (TEM) imaging, we have explored CaCO3 mineralization pathway regulated by Megabalanus rosa CP 20 (MrCP20). Our data show MrCP20 can sequestrate inorganic calcium carbonate ions state, which quickly coarsen into liquid-like microdroplets subsequently form protovaterite amorphous (ACC) particles. This leads stabilization metastable vaterite polymorphism CaCO3. Simultaneously, AFM TEM investigations undergoes fibrillization triggered pH drift arising during mineralization, leading amyloid-like nanofibrils. Based on protein NMR, mechanism appears be stabilized reduction intramolecular disulfide bonds. Collectively, our results demonstrate plays synergistic while concomitantly self-assembling