Improvement of the chemical and physical stability of the EC1 domain of E-cadherin by blocking its disulfide-mediated dimerization

Abstract

The EC1 protein has an important role in the E-cadherin mediated cell-cell adhesion in epithelial and endothelial tissues. It may be used as modulator of cellular adhesion to improve paracellular delivery of macromolecules. EC1 undergoes oxidation of its Cys residue to form disulfide-linked covalent dimers. These dimers associate to form physical oligomers. The dimerization and oligomerization also lead to hydrolysis of the Asp93-Pro94 peptide bond and precipitation. To be able to study the cell adhesion-modulating activity of EC1, it is important that we block its disulfide-dimerization and subsequent oligomerization. The strategies used to block the dimerization were addition of dithiothreitol to the EC1 solution, modification of the Cys thiol with iodoacetamide and polyethylene glycol. These derivatives were studied for their stability using HPLC, CD and fluorescence spectroscopy. All strategies applied showed improvement in the stability of EC1. The PEGylated EC1 showed the best stability.