FIGURE 5.
In vitro binding of selected EpaA domains. A, dissociation constants (KD values) for binding of Epa1A, Epa6A, and Epa7A to five different galactosides (α1–3-galactobiose = Galα1–3Gal; β1–3-galactobiose = Galβ1–3Gal; T-antigen = Galβ1–3GalNAc; lacto-N-biose = Galβ1–3GlcNAc; and N-acetyl-d-lactosamine = Galβ1–4GlcNAc) were determined by fluorescence titration analysis and are shown in regular letters, including values for standard deviations. Binding values obtained for Epa1A, Epa6A, and Epa7A and the five galactosides on glycan arrays (corresponding array numbers are indicated in parentheses) are shown below KD values in italic letters. B, discrimination ratios with respect to different linkage types (β1–4/β1–3 and β/α) and with regard to the nature of the sugar moiety attached to galactose (Gal/GalNAc and GalNAc/GlcNAc) were calculated from the corresponding association constants (1/KD) obtained by fluorescence titration (ft) analysis or from the glycan array fluorescence signals (array) shown in A.