Figure 3 | Scientific Reports

Figure 3

From: Single tryptophan Y160W mutant of homooligomeric E. coli purine nucleoside phosphorylase implies that dimers forming the hexamer are functionally not equivalent

Figure 3

Differential fluorescence spectra of the E. coli PNP complexes with phosphate, left upper panel for the WT PNP (red), remaining graphs for the Y160W mutant (green), obtained at 25 °C, in 50 mM Tris/HCl buffer pH 7.6. The excitation wavelengths at which the spectra were measured are denoted on each graph. Phosphate concentrations were as follows: 10 μM, 100 μM, 1000 μM, 10 000 μM. The increase in phosphate concentration is marked with the gradient of the colour, black for the lowest, red (for the WT) or green (for the Y160W mutant) for the highest phosphate concentration. In the graphs for the Y160W mutant, the wavelengths chosen for the observation for each excitation wavelengths are marked by arrows. These data, together with the excitation wavelength shown on the graph, define conditions, in which titrations presented on Fig. 4, were performed. Direction of the arrows indicates only the direction of the phosphate concentration growth.

Back to article page