4NMQ

CFTR Associated Ligand (CAL) PDZ domain bound to peptide iCAL36(Ac-K-4) (ANSRW[Ac-K]TSII)

Summary for 4NMQ

• Entry DOI: 10.2210/pdb4nmq/pdb
• Related: 4NMO 4NMP 4NMR 4NMS 4NMT 4NMV
• Related PRD ID: PRD_001195
• Descriptor: Golgi-associated PDZ and coiled-coil motif-containing protein, iCAL36(Ac-K-4) peptide, GLYCEROL, ... (4 entities in total)
• Functional Keywords: cal, pist, gopc, fig, pdz, cftr, cftr associated ligand, pdz-peptide, protein transport-inhibitor complex, protein transport/inhibitor
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: Q9HD26
• Total number of polymer chains: 4
• Total formula weight: 21328.40

Authors

Amacher, J.F.,Madden, D.R. (deposition date: 2013-11-15, release date: 2014-10-01, Last modification date: 2023-12-06)

Primary citation

Amacher, J.F.,Zhao, R.,Spaller, M.R.,Madden, D.R.
Chemically Modified Peptide Scaffolds Target the CFTR-Associated Ligand PDZ Domain.
Plos One, 9:e103650-e103650, 2014

PubMed Abstract: PDZ domains are protein-protein interaction modules that coordinate multiple signaling and trafficking pathways in the cell and that include active therapeutic targets for diseases such as cancer, cystic fibrosis, and addiction. Our previous work characterized a PDZ interaction that restricts the apical membrane half-life of the cystic fibrosis transmembrane conductance regulator (CFTR). Using iterative cycles of peptide-array and solution-binding analysis, we targeted the PDZ domain of the CFTR-Associated Ligand (CAL), and showed that an engineered peptide inhibitor rescues cell-surface expression of the most common CFTR disease mutation ΔF508. Here, we present a series of scaffolds containing chemically modifiable side chains at all non-motif positions along the CAL PDZ domain binding cleft. Concordant equilibrium dissociation constants were determined in parallel by fluorescence polarization, isothermal titration calorimetry, and surface plasmon resonance techniques, confirming robust affinity for each scaffold and revealing an enthalpically driven mode of inhibitor binding. Structural studies demonstrate a conserved binding mode for each peptide, opening the possibility of combinatorial modification. Finally, we diversified one of our peptide scaffolds with halogenated substituents that yielded modest increases in binding affinity. Overall, this work validates our approach and provides a stereochemical foundation for further CAL inhibitor design and screening.

PubMed: 25136860
DOI: 10.1371/journal.pone.0103650

Experimental method

X-RAY DIFFRACTION (1.4 Å)