Location of engineered 664-1826 disulfide bond relative to other cysteine residues in the fVIIIa A domains. A trace linking each Ca atom of the fVIIIa A domain backbone is drawn (transparent colors) with the A2 domain in blue, and A3 domain in magenta. Cysteine residues are displayed as balls and sticks where black balls represent carbon atoms and colored balls sulfur atoms. Green represents native fVIIIa disulfide bonds whereas red represents native fVIIIa free cysteine residues. The engineered disulfide bond 664-1826 is drawn in yellow in the center. The closest distance between residues 664-1826 and other cysteine residues are shown as dotted black lines where the distances are between sulfur atoms.