FIG. 4.
Location of Exp1-ΔSPNuc, Nlp1-ΔSPNuc, and Tmp2-ΔSPNuc fusion proteins in L. lactis. Three L. lactis MG1363 derivative strains, each producing a representative member of each class of putative exported ΔSPNuc fusions (shown in parentheses), were examined: Exp (Exp1-ΔSPNuc), Nlp (Nlp1-ΔSPNuc), and Tmp (Tmp2-ΔSPNuc). Cell (C) and supernatant (S) fractions from mid-exponential-phase cultures of the above-mentioned strains were analyzed by SDS-PAGE and Western blotting using polyclonal Nuc antibodies. Putative forms of each fusion are indicated. Note that a band corresponding to a high-molecular-weight protein, visible in the cell fraction of the strain producing Nlp1-ΔSPNuc, is nonspecific and is observed in other samples.