Electrophoretic mobility shift assay. A. Binding of both SiaR and CRP to the nan-siaPT intergenic region. Both SiaR and CRP bind to the probe individually and CRP binding is dependent on the presence of cAMP. Both proteins bind the probe simultaneously as indicated by the higher shift of the probe when both proteins are added. B. GlcN-6P enhances binding of SiaR. Two-fold serial dilutions of SiaR were added to binding reactions in the absence and presence of 100 μM GlcN-6P. More probe was shifted when GlcN-6P was present.