The TF exosite and 4 × Ser loop form an interface that interacts with the GLA domains of both FX and FVIIa. All snapshots were taken at the end of the equilibrium simulations (total 550 nanoseconds). FX is colored in purple, TF in cyan, and FVIIa in orange. Key residues involved in any interactions are shown as sticks and labeled accordingly. Carbon atoms are colored according to their respective molecules, oxygen in red, nitrogen in blue, and hydrogen in white. The black arrow points to the TF 4 × Ser loop. Distances between atoms (in Å) are represented as brown dotted lines, whereas the hydrogen bond between FVIIa residue R36 and the TF backbone carbonyl at residue S160 is represented by a blue dotted line. (A) Closeup view of the TF 4 × Ser loop and exosite region, highlighting key residues in TF, FX, and FVIIa involved in TF:FVIIa or TF:FX interactions. (B) A 90°-rotated view of the TF 4 × Ser loop/exosite interface, providing an alternative view focused on the TF:FX interactions.