A “ligand-targeting” peptide-drug conjugate: Targeted intracellular drug delivery by VEGF-binding helix-loop-helix peptides via receptor-mediated endocytosis
Fig 2
The binding characteristics of M49.
(a) Schematic of the HLH peptide library. Spheres colored in green, red, and orange represent the positions of leucines inside of the helices, randomized residues in the loop region, and randomized residues on the C-terminal helix, respectively. (b) The binding affinity of M49 was determined via SPR. VEGF was immobilized by the amine coupling, and the peptides were injected as an analyte at different concentrations (50–3 nM). The data were fitted with the 1:1 Langmuir model. Black lines indicate the fitting curves. (c) Ternary complex formation consisting of M49, VEGF, and VEGFR-2 in the SPR assay. VEGF was injected at a concentration of 25 nM over immobilized VEGFR-2/Fc fusion protein followed by injection of M49 at a concentration of 250 nM (red line). A sensorgram of M49 (250 nM) for VEGFR-2 is shown as a black line. The injection points were represented as arrows.