Pharmacy and Pharmaceutical Sciences Commons^™

Cysteine Modifiers Suggest An Allosteric Inhibitory Site On The Cal Pdz Domain, Yu Zhao, Patrick R. Cushing, David C. Smithson, Maria Pellegrini, Alexandre A. Pletnev, Sahar Al-Ayyoubi, Andrew V. Grassetti, Scott A. Gerber, R. Kiplin Guy, Dean R. Madden

Pharmaceutical Sciences Faculty Publications

Protein–protein interactions have become attractive targets for both experimental and therapeutic interventions. The PSD-95/Dlg1/ZO-1 (PDZ) domain is found in a large family of eukaryotic scaffold proteins that plays important roles in intracellular trafficking and localization of many target proteins. Here, we seek inhibitors of the PDZ protein that facilitates post-endocytic degradation of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR): the CFTR-associated ligand (CAL). We develop and validate biochemical screens and identify methyl-3,4-dephostatin (MD) and its analog ethyl-3,4-dephostatin (ED) as CAL PDZ inhibitors. Depending on conditions, MD can bind either covalently or non-covalently. Crystallographic and NMR data confirm that MD …