Fig. 5: Molecular mechanism of snFPITE-mediated thrombolysis.

a Crystal structure of snFPITE-n1. The α-helices of the structure are indicated in blue, the β-sheets in pink, and the loops in gray. b Crystal structure of snFPITE-n2. The α-helices of the structure are indicated in blue, the β-sheets in pink, and the loops in gray. c Structure of snFPITE-n1 (shown as a pink cartoon) superimposed with tPA (PDB: 1A5H, shown as a green cartoon). d Model of snFPITE-n1 in complex with a canonical human plasminogen peptide 576-KCPGRVVGGCAH-588 (gray sticks) showed that there was no steric clash between them. e Model of snFPITE-n1 superimposed with the tPA in complex with an inhibitor (PDB: 1A5H). f Structure of snFPITE-n1 superimposed with plasmin (PDB:1BUI, shown as an orange cartoon). g Structure of snFPITE-n1 superimposed with plasmin in complex with a peptide mimic inhibitor (PDB: 1BUI). h Molecular interaction between snFPITE and fibrinogen. Three independent experiments were repeated with similar results. i Model of snFPITE-n1 in complex with PAI1 and plasminogen peptide. PAI1 (blue) blocked the way such that the plasminogen peptide 576-KCPGRVVGGCAH-588 (yellow) was bound to the snFPITE-n1 (pink). j Model of snFPITE-n1 in complex with A2AP and fibrinogen peptide. A2AP (gray) competed with the fibrinogen peptide 576-KCPGRVVGGCAH-588 (yellow) bound to the snFPITE-n1 (pink). Source data are provided as a Source Data file.