FIGURE 6.

Fluorescence titration measurements on binding of LeishIF4E-1 to cap analogs. LeishIF4E-1 proteins, at a concentration of 0.3 μM, were titrated by the cap analogs: cap-4 (open squares), m⁷GTP (open circles), m⁷GpppA (black squares), m⁷ Gpppm₃^6,6,2′A (open triangles), and GTP (black triangles), at 20°C in 50 mM HEPES/NaOH, 100 mM NaCl, 1 mM EDTA, 1 mM DTT. Protein fluorescence, presented as relative values, was excited at 295 nm and observed at 345 nm. The observed increasing fluorescence intensity at a higher concentration of ligand originates from the emission of the free cap analogs in solution.