Figure 2.

Binding modes of the 5 candidate peptides housed in the substrate-binding region of GRP78 (PDB: 5E84). They are represented here by white surface (top) and green cartoon (bottom). The interacting residues of GRP78 are colored in orange in the surface representation. The interaction of the satpdb18674 peptide residues (GLN-1, SER, and THR-7) with the residues (VAL-429, GLN-449, and SER-452) of the GRP78-binding site. The peptide satpdb18446 residues TYR-3, ASN-4, VAL-1, and THR-10 interacted with THR-434, VAL-429, GLN-449, and SER-452 of the same target. For satpdb12488 residues, ASP-19, THR-2, ASP-16, and MET-5 interacted with the THR-434, VAL-429, LYS-447, PHE-451, and SER-452 of the GRP78. The residues (ILE-13, SER-12, and THR-9) of satpdb14438 interacted with GRP78 residues THR-434, VAL-429, and THR-458. Finally, the peptide satpdb28899 residues ASP-20, LEU-19, SER-16, and THR-15 interacted with VAL-429 and THR-458 from the same region. The 5 compounds established multiple hydrogen bonds with the residues of the GRP78 substrate-binding pocket. Interactions with V429 and S452 were observed in the 5 peptides, except for satpdb28899 (V429 only). satpdb12488, satpdb14438, and satpdb18446 interacted with THR-434; satpdb14438 and satpdb28899 interacted with GLN-449; satpdb14438 and satpdb28899 interacted with THR-458; and satpdb12488 interacted with LYS-447 and PHE-451. GRP indicates glucose-regulating protein.