The structure of recombinant NP-1 proteins.

(A) Schematic representation of the Fc-tagged NP-1 extracellular segment (NP-1–Fc) and Flag-tagged NP-1 extracellular segment (NP-1–Flag). (B) SDS-PAGE analysis of the recombinant proteins stained with Coomassie brilliant blue G-250. (C) Immunoblot of the recombinant proteins with the antirabbit NP-1 antibody.14 Lanes 1-4 correspond to NP-1–Flag (1), NP-1–Fc (2), NP-1–Flag (3), and NP-1–Fc (4) recombinant proteins; 1 and 2 were under nonreducing conditions and 3 and 4 were under reducing conditions.