Constructs of ADAMTS13 and truncated variants. The full-length ADAMTS13 (FL-A13) and the variants truncated after the eighth TSP1 repeat (delCUB) and after the spacer domain (MDTCS) were cloned into pcDNA3.1 V5-His TOPO vector. The original signal peptide and propeptide of ADAMTS13 were included. The CUB domains (CUB, C1192-T1427), T2-8 repeats (T2-8, W686-W1076), T5-8 repeats (H884-W1076), the CUB domains plus the TSP1 5-8 repeats (T5-8CUB, H884-A1191), and the CUB domains plus the TSP1 2-8 repeats (T2-8CUB, W686-A1191) were cloned into pSecTag/FRT/V5-His TOPO, in which an IgK secretion peptide and a Flag epitope (-DDDDK-) were engineered at the N terminus of the CUB, T2-8, T5-8, T5-8CUB, and T2-8CUB. All constructs contain V5-His epitopes at their C termini to facilitate purification and detection.