Surface representation of ADAMTS13-DTCS and close view of the Tyr⁶⁵⁸-Tyr⁶⁶⁵ motif in the spacer domain. Panels A and C are the surface representations of ADAMTS13-DTCS fragment on the basis of the crystal structure reported by Akiyama et al.⁴¹  The amino acids facing away are labeled in gray, whereas those facing toward are in black. Panels B and D are the close views of the motif (Tyr⁶⁵⁸-Tyr⁶⁶⁵) within which the residues Arg⁶⁵⁹, Arg⁶⁶⁰, Tyr⁶⁶¹ are located. These residues may directly interact with the central A2 domain of VWF. The Gly⁶⁶² is buried, but Glu⁶⁶³ and Glu⁶⁶⁴ point to the opposite direction of the residues Arg⁶⁵⁹, Arg⁶⁶⁰, Tyr⁶⁶¹ (also see the video in supplemental Figure 2). R, Y, G, and E are single-letter abbreviations of the amino acids arginine, tyrosine, glycine, and glutamic acid.