FIGURE 3.

NMR analysis of the activity of BT3780. ¹H NMR spectra were recorded in D₂O on a Bruker Avance III HD 500 MHz NMR spectrometer operating at 500.15 MHz. The chemical shift is quoted in ppm relative to tetramethylsilane, and each spectrum was acquired with 16 scans. The spectrum of 10 mg/ml C. albicans mannan in 20 mm sodium phosphate, pH 7.5, 100 mm NaCl, was recorded prior to and after addition of 30 μm BT3780, at the time points indicated on the graph. A peak at the chemical shift corresponding to the H-1α proton of mannose (5.10 ppm) was detected after 2 min, and mutarotation to the β-anomer was observed subsequently (4.82 ppm), indicating that the reaction proceeds with inversion of anomeric configuration. Spectra of mannose and mannose-1-phosphate (anomeric hydrogen 5.28 ppm) in reaction buffer are also shown.