Disordered linker between D3 and A1. (A) Illustration of the VWF amino-terminal segment showing the disordered regions in the tubule (missing density). (B) The end point of a D3 assembly modeled into the tubule map (residue 1197) and the start point of the 2 nearest A1 domains (residue 1263) are indicated by black circles. Dashed lines indicate the 2 possible connectivities with distances indicated. The shorter distance is not necessarily the more likely to represent a covalent connection.