Figure 1.

Expression of recombinant MUC5B protein domains. A, schematic showing the domain structure of N- and C-terminal constructs of MUC5B. The constructs were composed of a N-terminal His₆ tag (gray square) coupled to the MUC5B domains, NT5B (D1-D2-D′-D3) and CT5B (D4-B-C-CK). B, N- and C-terminal constructs, reduced (R) with 10 mm DTT and nonreduced (NR), were analyzed by SDS-PAGE, and stained with InstantBlue. Gel splicing occurred at the position indicated by the dashed line, the data came from the same gel. C, recombinant CT5B in 0.2 m NaCl, pH 7.4, was analyzed by SEC-MALS and the representative graph shows the differential refractive index. The chromatograph showed two peaks corresponding to dimer (peak II) and monomer (peak I). Experiments were repeated at least 3 times.