Production of mutant and wild-type LbpBs.

<p>Expression experiments were performed with plasmids carrying the gene encoding aa 54–737 of the mature wild-type LbpB (WT) from <i>N. meningitidis</i> strain MC58, a derivative with the large negatively charged region removed (−LG, aa 469–533) and a derivative with both the large and small negatively charged regions removed (−LG, aa 469–533; -SM, aa 691–721). The recombinant fusion proteins containing an N-terminal polyhistidine tag, a maltose binding protein and a tobacco etch virus protease cleavage were expressed in an <i>E. coli</i> T7 based expression system and isolated by a nickel NTA affinity resin. Purified samples normalized to equivalent quantities of the original culture volume were applied to an 8% polyacrylamide SDS-PAGE gel and stained for protein. The upper bands found around ∼125kDa represent the recombinant fusion proteins whereas the lower bands represent LbpB released from Mbp.