Figure 4

Position 17 in the basic region of bZIP TFs is important for specifying Yap versus Gcn4 half-sites. (a) ClustalW2 alignment of the basic regions of eight yeast bZIP proteins, and the corresponding DNA binding site motifs. (b) Sko1 (which contains a phenylalanine at position 17 in the basic region, similar to Yap proteins) has a stronger preference for adjacent Yap half-sites compared to Gcn4 and Cst6 (which contain serine and cysteine at position 17, respectively). (c) The trend observed in (b) is not simply due to the fact that Sko1 prefers adjacent half-sites to overlapping half-sites. If this were the case, we would expect Gcn4 to bind overlapping Yap half-sites with higher affinity than Sko1, but we do not observe such a trend.