Mutagenesis and expression of ADAMTS13 disintegrin-like domain mutants. (A) Amino acid sequence alignment of the disintegrin-like domain of all ADAMTS family members. (B) Amino acid sequence of the ADAMTS13 disintegrin-like domain. In panels A and B, the linker region that wraps behind the metalloprotease domain is shown. The variable segment (VS) and the hypervariable region (HVR) are boxed. In panel B, the amino acids in bold are those that were mutated and analyzed in this study. (C) Wild-type and mutant ADAMTS13 were expressed in HEK293T cells. After 3 days, expression and secretion were analyzed by Western blot analysis of conditioned media using an anti-ADAMTS13 pAb.