Figure 7.

Intrinsic tryptophan fluorescence of the wild-type and L298W hGBP-1 proteins in the absence and presence of the substrate analog GppNHp. A similar experiment was carried out with equimolar mixture of the wild-type and L298W. The concentration of total protein was kept at 0.5 μM. One-hundred micromole of the analog was used for the assay. The samples were excited at 280 nm and the fluorescence emission spectra were recorded between 290 and 450 nm. A blank containing the buffer as described in the Materials and Methods was subtracted from each spectrum. Each spectrum was recorded as the average of three fluorescence emission wavelength scans. The experiments were carried out in triplicate and the results were consistent.