Figure 10. Comparison of WT and an equimolar mix of the four repeats by tryptophan quenching

Quenching of tryptophan fluorescence by all-trans-retinol was used to compare the intact IRBP molecule versus a mixture of the four repeats. Trp fluorescence was measured by excitation at 280 nm and emission at 336 nm. The same assay conditions were employed as in Figure 9. The error bars indicate the standard error of the mean. The same symbols and colors are used as in Figure 9. The four repeats mixed together exhibit similar binding behavior to intact WT IRBP.