P textilis–motivated FV mutant. (Left) Sequence alignment of the C2 domains from human FVIII (H-FVIII-C2), human FV (H-FV-C2), bovine FV (B-FV-C2), and the FV-homologous subunit of pseutarin C from P textilis venom (Pt-FV-C2). Black bars represent the 4 lipid binding spikes with the hydrophobic residues marked with triangles. Amino acids that were mutated to make FV_MTTS/Y are starred. (Right) Locations of the mutated amino acids on the C2 domain of human FV are shown with original side chains in dark gray with the rest of the backbone in light gray. Residue numbers relate to the full-length human FV. Numbering references follow HGVS standard, using Met of respective propeptides as 1.