FIG. 3.

Purification and characterization of His-tagged L. casei ThiT and FolT. (A and B) SDS-PAGE of purified ThiT-His and FolT-His, as in Fig. 2A. (C) Fluorescence spectrum of ThiT-His (320 nM in 50 mM K phosphate, 200 mM KCl, 0.05% [wt/vol] DDM, pH 7.0) in the absence of thiamine (uppermost trace) and in the presence of successively higher concentrations of thiamine (up to 400 nM). (D) Fluorescence titration of ThiT-His with thiamine. (E and F) Fluorescence titration of FolT-His (210 nM in 50 mM K phosphate, 200 mM KCl, 0.05% [wt/vol] DDM, pH 7.0) with (6S)-folinic acid (E) and folic acid (F).