Figure S1: Chromatogram of peptide A. The * indicates the fraction referring to the reduced peptide.

Figure S2: Chromatogram of peptide A after oxidation. (1) oxidized peptide and (2) reduced peptide.

Figure S3: MS spectrum of oxidized peptide A. Presence of the mass referring to the oxidized peptide A with single charge ([M + H]+ = 1667.683 Da).

Figure S4: MS/MS spectrum referring to the fragmentation of the precursor ion of peptide A. The experiment were acquired in the positive ion mode.

Figure S5: Chromatogram of peptide B. The * indicates the fraction referring to the reduced peptide.

Figure S6: Chromatogram of peptide B after oxidation. (1) oxidized peptide and (2) reduced peptide.

Figure S7: MS spectrum of oxidized peptide B. Presence of the mass referring to the oxidized peptide B with single charge ([M + H]+ = 1695.688 Da).

Figure S8: MS/MS spectrum referring to the fragmentation of the precursor ion of peptide B. The experiment were acquired in the positive ion mode.

Figure S9: Chromatogram of peptide C. The * indicates the fraction referring to the reduced peptide.

Figure S10: Chromatogram of peptide C after oxidation. (1) oxidized peptide and (2) reduced peptide.

Figure S11: MS spectrum of oxidized peptide C. Presence of the mass referring to the oxidized peptide C with single charge ([M + H]+ = 1676.489 Da).

Figure S12: MS/MS spectrum referring to the fragmentation of the precursor ion of peptide C. The experiment were acquired in the positive ion mode.

Figure S13: Chromatogram of peptide D. The * indicates the fraction referring to the peptide.

Figure S14: MS spectrum of oxidized peptide D. Presence of the mass referring to the oxidized peptide D with single charge ([M + H]+ = 1429.607 Da).

Figure S15: MS/MS spectrum referring to the fragmentation of the precursor ion of peptide D. The experiment were acquired in the positive ion mode.

Figure S16: Chromatogram of peptide E. The * indicates the fraction referring to the peptide.

Figure S17: Chromatogram of peptide E after oxidation. The * indicates the fraction referring to the oxidized peptide.

Figure S18: MS spectrum of oxidized peptide E. Presence of the mass referring to the oxidized peptide E with single charge ([M + H]+ = 1457.423 Da).

Figure S19: MS/MS spectrum referring to the fragmentation of the precursor ion of peptide E. The experiment were acquired in the positive ion mode.

Figure S20: MS/MS spectrum referring to the fragmentation of the precursor ion of peptide F. The experiment were acquired in the positive ion mode.

Figure S21: Mass spectrum of peptide E acquired in an ESI micrOTOF II (Bruker Daltonics, Germany). The highest intensity ion concerns the double charge form of the peptide ([M + 2H]2+ = 729.8172 Da). The experiment were acquired in the positive ion mode.

Figure S22: Mass spectrum of peptide E acquired in an ESI micrOTOF II (Bruker Daltonics, Germany). The double and the triple charge forms are observed. The experiment were acquired in the positive ion mode.

Figure S23: Mass spectrum of peptide E acquired in an ESI micrOTOF II (Bruker Daltonics, Germany). Amplified region referring to the double charge form of the peptide E ([M + 2H]2+ = 729.8172 Da). The experiment were acquired in the positive ion mode.

Figure S24: Hydrogen and carbon chemical shift assignment for peptide A.

Figure S25: Hydrogen and carbon chemical shift assignment for peptide B.

Figure S26: Hydrogen and carbon chemical shift assignment for peptide C.

Figure S27: Hydrogen and carbon chemical shift assignment for peptide D.

Figure S28: Hydrogen and carbon chemical shift assignment for peptide F.

Figure S29: Dihedral angles Φ and Ψ calculated by TALOS program for the peptides A, B and C.

Figure S30: Dihedral angles Φ and Ψ calculated by TALOS program for the peptides D and F.

Figure S31: NOE assignment and distance restraint for peptide A.

Figure S32: NOE assignment and distance restraint for peptide B.

Figure S33: NOE assignment and distance restraint for peptide C.

Figure S34: NOE assignment and distance restraint for peptide D.

Figure S35: NOE assignment and distance restraint for peptide F.

Figure S36: The calculated structures for the peptides A, B, C, D and F by simulated annealing method, using NMR parameters. Overlapping of the 20 lower energy structures for each peptide.

Figure S37: Root mean square deviation (RMSD) of the peptide E structure over a 10 nanoseconds molecular dynamic simulation in a water box using GROMACS software.

Figure S38: The radius of gyration of the peptide E structure over a 10 nanoseconds molecular dynamic simulation in a water box using GROMACS software.

Figure S39: The system enthalpy energy of the peptide E simulation over a 10 nanoseconds in a water box using GROMACS software

Figure S40: Comparison between the three-dimensional ligand-receptor structure of peptides A, B, C, D and F after molecular docking experiments in silico. In gray, the main residues of site αIIbβ3 are highlighted, where molecular interaction with the ligands occurs.

Figure S41: Interaction diagram of eptifibatide docked into the activation site of αIIbβ3 integrin.

Figure S42: Interaction diagram of peptide A docked into the activation site of αIIbβ3 integrin.

Figure S43: Interaction diagram of peptide B docked into the activation site of αIIbβ3 integrin.

Figure S44: Interaction diagram of peptide C docked into the activation site of αIIbβ3 integrin.

Figure S45: Interaction diagram of peptide D docked into the activation site of αIIbβ3 integrin.

Figure S46: Interaction diagram of peptide E docked into the activation site of αIIbβ3 integrin.

Figure S47: Interaction diagram of peptide F docked into the activation site of αIIbβ3 integrin.