Fig. 1.

Schematic representation of P3H1, CRTAP, and PPIB variants. Various constructs were prepared to explore the interactions among P3H1/CRTAP/PPIB complex members. Blue squares represent the signal peptides of each construct, red squares represent the KDEL sequence of P3H1, and the yellow stars represent the His₆ sequence. P3H1 with the KDEL sequence removed from the tail was named PD4. The N-terminal segment of P3H1 (1–446) was named PD4-N-His, and the C-terminal dioxygenase segment (447–732) was named PD4-C-His. Sumo-PPIB variant was expressed in E. coli, and all other P3H1, CRTAP, and PPIB variants were prepared from HEK 293E cells