Figure 11

Analysis of locations and phenotypes of nine randomly induced substitutions in the binding domain of IS 2 OrfAB. Location of the three α helix bundle which constitutes the binding domain (green cylinders) is based on the prediction of the PBIL-PHD Secondary Structure Analysis Algorithm ([55]; see Figure 9b). The sequence in red indicates the prospective HTH motif identified by the PBIL- HTH Determination Algorithm of Dodd and Egan [56]. The Pabo and Sauer [95] consensus sequence for prokaryotic HTH motifs is shown within the large brackets and correlates well with this prospective motif (red lettering). Four of the nine mutations fell within this 12-residue consensus sequence including the double mutation represented by the combination of the red bracket and the hooked arrow. The phenotype of this double mutation is indicated by the vertical red arrow. Binding efficiencies are as described in Figure 6 and transposition frequencies were calculated as described in Table 2.