Structural details of the VWF CTCK dimer. (A) The hydrophobic pocket underlying the β4 and β5 strands and the β4-β5 loop in the dimer interface. Sidechains that interact across the interface are shown in stick. A2801 and P2776, involved in VWD mutations, are shown with sphere Cα atoms. (B) VWD mutations. Mutated residues are marked with Cα spheres and their native sidechains are shown in stick (some also appear in A). Disulfide bonds are shown, whether or not their cysteines are mutated in VWD. (C) Stereoview showing the high density of backbone hydrogen bonds (dashed) and disulfides in the dimerization interface. The view includes all inter-chain disulfides and the CK in each monomer.