The isolated armadillo-repeat domain of Plakophilin 1 is a monomer in solution with a low conformational stability
A. Marcela Giudici, José G.Hernández-Cifre, Ana Cámara-Artigas, Felipe Hornos, Sergio Martínez-Rodríguez, Juan Carlos Alvarez-Pérez, Inés Díaz-Cano, María Esther Fárez-Vidal, José L Neira
Journal of Structural Biology
Plakophilin 1 (PKP1) is a member of the armadillo repeat family of proteins. It serves as a scaffold component of desmosomes, which are key structural components for cell–cell adhesion. We have embarked on the biophysical and conformational characterization of the ARM domain of PKP1 (ARM-PKP1) in solution by using several spectroscopic (namely, fluorescence and circular dichroism (CD)) and biophysical techniques (namely, analytical ultracentrifugation (AUC), dynamic light scattering (DLS) and differential scanning calorimetry (DSC)). ARM-PKP1 was a monomer in solution at physiological pH, with a low conformational stability, as concluded from DSC experiments and thermal denaturations followed by fluorescence and CD. The presence or absence of disulphide bridges did not affect its low stability. The protein unfolded through an intermediate which has lost native-like secondary structure. ARM-PKP1 acquired a native-like structure in a narrow pH range (between pH 6.0 and 8.0), indicating that its adherent properties might only work in a very narrow pH range.
Circular dichroism, Secondary structure, Chemical stability, Thermal stability, Protein folding, Protein denaturation, Biochemistry