The relative orientation between VWF-D′ and D3 in BIVV001 is rotated compared with the previously reported X-ray structure of VWF-D′D3 alone. (A) Superposition of the VWF-D′D3 X-ray structure (PDB: 6N29), via D′, onto the D′D3 portion of the BIVV001 structure. (B) The individual structures from panel A viewed from the top, placing the long axis of D′ pointed out of the page. The 85° relative rotation of VWF-D3 is indicated by the gradient arrows. (C) The same superposition and transition shown in in the context of the full BIVV001 structure. VWF-D3 rotates 85°, moving the C8-3 α-helices 30 Å to contact FVIII C2.