PDBsum entry 4nmq

Protein transport/inhibitor

PDB id: 4nmq

Contents

Protein chains

87 a.a.

Ligands

ALA-ASN-SER-ARG-TRP-ALY-THR-SER-ILE-ILE ×2

GOL ×2

Waters ×197

PDB id:

4nmq

Name:

Protein transport/inhibitor

Title:

Cftr associated ligand (cal) pdz domain bound to peptide ical36(ac-k- 4) (ansrw[ac-k]tsii)

Structure:

Golgi-associated pdz and coiled-coil motif-containing protein. Chain: a, b. Fragment: unp residues 284-370. Synonym: cftr-associated ligand, fused in glioblastoma, pdz protein interacting specifically with tc10, pist. Engineered: yes. Ical36(ac-k-4) peptide. Chain: c, d.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: gopc, cal, fig. Expressed in: escherichia coli. Expression_system_taxid: 469008. Synthetic: yes

Resolution:

1.40Å R-factor: 0.182 R-free: 0.199

Authors:

J.F.Amacher,D.R.Madden

Key ref:

J.F.Amacher et al. (2014). Chemically modified peptide scaffolds target the CFTR-associated ligand PDZ domain. Plos One, 9, e103650. PubMed id: 25136860 DOI: 10.1371/journal.pone.0103650

Date:

15-Nov-13 Release date: 01-Oct-14

Protein chains

Q9HD26  (GOPC_HUMAN) -  Golgi-associated PDZ and coiled-coil motif-containing protein from Homo sapiens

Seq: 462 a.a.

Struc: 87 a.a.

DOI no: 10.1371/journal.pone.0103650

Plos One 9:e103650 (2014)

PubMed id: 25136860

Chemically modified peptide scaffolds target the CFTR-associated ligand PDZ domain.

J.F.Amacher, R.Zhao, M.R.Spaller, D.R.Madden.

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.