Table 2. Affinity for melibiose and Na+.
Melibiose displacement of D2G (IC50, mM) | Na+ activation constant for D2G FRET (K0.5, mM) | |
---|---|---|
WT MelBSt | 2.65±0.80* | 1.92±0.78 |
R295C | 4.04±0.42 | 3.22±1.07 |
R141C | 5.93±1.61 | 4.77±0.39 |
R363C | 2.83±0.57 | 5.51±1.07 |
D2G, 2′-(N-dansyl)aminoalkyl-1-thio-β-D-galactopyranoside; FRET, fluorescence resonance energy transfer; MelBSt, Salmonella typhimurium melibiose permease; WT, wild type.
*s.e.m., n=2.