IDIBE, Universidad Miguel Hernández, 03202 Elche Alicante, Spain.
Departamento de Química Física, Facultad de Química, Campus de Espinardo, Universidad de Murcia, 30100 Murcia, Spain.
J Struct Biol. 2020 Sep 1;211(3):107569. doi: 10.1016/j.jsb.2020.107569. Epub 2020 Jul 7.
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.
桥粒斑蛋白 1（PKP1）是桥粒斑蛋白家族的一员。它作为桥粒的支架成分，桥粒是细胞间黏附的关键结构成分。我们通过使用几种光谱（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）），对 PKP1 的 ARM 结构域（ARM-PKP1）在溶液中的生物物理和构象特性进行了研究。ARM-PKP1 在生理 pH 值下为单体，从 DSC 实验和荧光和 CD 跟踪的热变性得出，其构象稳定性较低。二硫键的存在与否并不影响其低稳定性。该蛋白通过失去天然二级结构的中间状态展开。ARM-PKP1 在一个狭窄的 pH 范围内（6.0 到 8.0 之间）获得了类似天然的结构，表明其附着特性可能仅在非常狭窄的 pH 范围内起作用。
