Download and normalize reference affinity datasets. Absolute affinity datasets which measure ∆∆G or Kd do not need to be normalized. Relative affinity datasets must be normalized such that the maximum affinity DNA binding site is 1.0 and all other binding sites are relative that. Techniques which measure relative affinity include Protein Binding Microarrays (PBM), Systematic evolution of ligands by exponential enrichment (SELEX), ChIP-seq, and others. Normalizing relative affinity datasets requires a core binding site defined using IUPAC nomenclature. The core binding site is determined using a combination of crystal structure, high-quality PWM and, when available, functional assays (more information on defining a core binding site here). The DNA sequence with the highest affinity site containing the core is v1.0, with all other sequences relative to this.