Hydrophilic photolabelling of glycopeptides from the murine liver-intestine (LI) cadherin recognition domain

LI-Cadherin is a transmembrane glycoprotein involved in cell adhesion of epithelial cells. Its supposed recognition domain contains the peptide motif AAL and is distinctly hydrophobic. In order to obtain sufficiently soluble model compounds, glycan side chains of T-antigen, (2,6)sialyl T-antigen and sialyl TN-antigen structure were linked to the serine located in the supposed turn sequence of the LI-cadherin recognition domain. A quinic acid-glycine-7-amino-coumarine (Quiglac) chromophore was constructed in order to enhance the solubility of labelled LI-cadherin (glyco)peptides in water.