Self-assembled peptide P11-4 interacts with the type I collagen C-terminal telopeptide domain and calcium ions

Evaluate molecularly the role of P11-4 self-assembly peptide in dentin remineralization and its interaction with collagen I. Methods: The calcium-responsive P11-4 peptide was analyzed by intrinsic fluorescence emission spectrum, circular dichroism spectrum (CD), and atomic force microscope (AFM). Differential light scattering was used to monitor the nucleation growth rate of calcium phosphate nanocrystals in the absence or in the presence of P11-4. AFM was used to analyze the radial size (nm) of calcium phosphate nanocrystals formed in the absence or in the presence of P11-4, as well as to verify the spatial structure of P11-4 in the absence or in the presence of Ca2+. Results: The interaction of Ca2+ with the P11-4 (KD = 0.58 ± 0.06 mM) promotes the formation of β-sheet antiparallel structure, leads to its precipitation in saturated solutions of Ca/P = 1.67 and induces the formation of parallel large fibrils (0.6 – 1.5 µm). P11-4 organized the HAP nucleation by reducing both the growth rate and size variability of nanocrystals, analyzed by the F test (p