Figure 3.

Chi_Ll is specifically recognized by RexAB. E. coli strains containing plasmid pRC2 with Chi_Ll or Chi_Ec were grown to mid-logarithmic phase, and whole-cell lysates were prepared. HMW was detected by Southern hybridization by using pRC2 as probe. Plasmids are: pRC2-Chi_Ll^m (containing mutated Chi_Ll, χ_Ll^m lanes), pRC2-Chi_Ll^1–2 (containing head-to-head copies of Chi_Ll, χ_Ll^1–2 lanes), pRC2-Chi_Ll¹ (containing Chi_Ll in orientation 1, χ_Ll¹ lanes), pRC2-Chi_Ll² (containing Chi_Ll in orientation 2, χ_Ll² lanes), pRC2-Chi_Ec² (containing Chi_Ec in orientation 2, χ_Ec lanes). Smear and bands below HMW in V186[pRexAB] strain appear to be secondary products of HMW accumulation.