Expression analysis of recombinant scFv-intimin. E. coli BL21(DE3)pLysS total extracts analyzed by electrophoretic profile in 12% SDS/PAGE. Lane 1. Molecular weight marker (LMW 97 to 14.4 kDa). Lane 2. Total bacterial extract before induction. Lane 3. Total bacterial extract 5 h after induction. Lane 4. Soluble fraction of bacterial extract. Lane 5. Insoluble fraction of bacterial extract (inclusion bodies) treated with 8 M urea. Recombinant protein of interest indicated by the arrow.