Figure 2 .

TF structural families and TFBS clusters. As many TFs cannot be distinguished in their binding specificity, clustering TF binding profiles promotes user consideration of all members of a functionally equivalent group. As TFs within a group bind to essentially identical sequences, users should focus on those TFs within a group likely to be active in a cell or condition relevant to their research. In the figure, the outer shapes and color represent the structural class, and the inner shapes symbolize the binding specificity of a cluster. The different shading within the shapes denotes individual TFs.