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.

Plakophilin 1 (PKP1) 是犰狳重复蛋白家族的成员。它作为桥粒的支架组分，桥粒是细胞-细胞粘附的关键结构组分。我们已经通过使用几种光谱（即荧光和圆二色性 (CD)）和生物物理技术（即分析超速离心 (AUC)、动态光散射（DLS）和差示扫描量热法（DSC））。ARM-PKP1 在生理 pH 下是溶液中的单体，具有低构象稳定性，如 DSC 实验和热变性，随后是荧光和 CD。二硫桥的存在与否不影响其低稳定性。蛋白质通过失去天然二级结构的中间体展开。ARM-PKP1 在狭窄的 pH 范围内（pH 6.0 和 8.0 之间）获得了类似天然的结构，表明其粘附特性可能仅在非常窄的 pH 范围内起作用。