FIG 5.

Recombinant expression of rNanI species corresponding to protease-cleaved NanI fragments. rNanI species corresponding to full-length NanI or the major 65-kDa chymotrypsin-cleaved or 60-kDa mouse SI fluid-cleaved NanI fragments were recombinantly expressed by using E. coli Top10 cells and the pTrc-HisB expression system. The rNanI species were then affinity enriched from the E. coli culture by using Talon resin and dialyzed overnight against PBS. Panel A shows the dialyzed samples subjected to SDS-PAGE and then either stained with Coomassie blue (left) or Western blotted for NanI (right). The relative amount of each enriched rNanI species was then determined by a protein assay. All experiments were performed in triplicate, and the mean results are shown. Error bars show standard deviations. # indicates a significant (P < 0.05) difference compared to full-length rNanI, and * indicates a significant (P < 0.05) difference compared to the rNanI species corresponding to the ∼65-kDa NanI fragment generated by chymotrypsin treatment.