Western blot showing detection of 0.1 μg recombinant proteins in Western blot. Lane 1: Molecular weight markers. Lane 2: MBP-ErpN/OspE fusion protein (arrow; 59.5 kDa expected MW). Lane 3: fusion protein (MBP-tagged) plus cleaved fusion proteins (without MBP). Lane 4: MBP alone. The lower bands are probably breakdown products. The upper bands in lane 3 are fusion protein (top band), or breakdown products of the fusion protein (bands in middle of blot). Protein was run on a 4-20% gel, then transferred to 0.45 μm nitrocellulose. After blocking with 1% BSA-TTBS overnight at 4ºC, primary antibody was used at 1:1000 at room temperature for 30 min. HRP-conjugated Goat-Anti-Rabbit secondary antibody was used at 1:40,000 in blocking buffer and imaged on the VersaDoc MP 4000 imaging system (Bio-Rad).