Fig. 1.

Expression of the fusion immunity gene flciA and purification of proteins that form complex with fLciA. (A) Coomassie-stained SDS/PAGE gel (Left) and immunoblot (Right) showing the presence of the fusion protein fLciA in the cell extracts (each 100 μg) of L. lactis Il1403-derived clones: B244 expressing lcnA and flciA and B268 expressing only flciA; B100, containing the empty vector, was used as negative control. (B) Silver-stained SDS/PAGE gel showing fLciA and its copurified proteins from Il1403-derived clones. B100, B244, and B268 were grown in the absence (first four lanes) or presence (last two lanes) of an exogenously added bacteriocin concentrate (final 50 BU/ml in +B1 and 200 BU/ml in +B2). In lane (−B), a nonbacteriocin concentrate from B100 was added as a control. (C) Silver-stained SDS/PAGE gel showing fLciA and its copurified proteins from MG1363-derived clones: B105 containing empty vector (control), B440 expressing lcnA and flciA, and B434 expressing only flciA. Samples were purified from cultures grown in the absence (B105, B440, and B434) or presence (B440+ and B434+) of added lactococcin A (100 BU/ml). Bars signify protein molecule weight markers, arrows signify fLciA and the copurified proteins (I, II, and III). For B and C, equal volumes of the eluted fractions (each 5 μl of total 100 μl) were applied to wells for direct comparison. ∗, a protein(s) that cross-reacted with the antibody M2.