Figure 1. Binding of C-terminal peptides to PDZ domains

The binding of synthetic peptides to dot-blotted GST fusion proteins representing PDZ domains. Lane 1: a peptide that models the C-terminus of CD81 Lane 2: a peptide without the putative PDZ binding domain. Lane 3: the binding of a scrambled protein. Specific binding was observed for the Sap97 domain 3, the protein-tyrosine phosphatase domain 1 (PTP-D1), and the X11L2 protein domain 1 (Mint-D1). Each PDZ domain is spotted with two concentrations of protein: 400 ng (upper spot) and 80 ng (lower spot). GST represents glutathione S-transferase.