Table 1. Comparison of Basic Biophysical Properties between Maize SUT1-WT and Its Mutants That Were Used for Ipre Measurements and VCF (− = no, + = yes, ++ or +++ indicates the intensity of fluorescence changes).
| Biophysical Properties of Maize SUT1 | The Wild Type | Cys-3 | Y61C | V62C | T64C | T72C |
|---|---|---|---|---|---|---|
| Mean Itr at −100 mV pH 4.0 (µA) | −3.3 ± 0.7 | −1.9 ± 0.3 | −0.8 ± 0.1 | −2.0 ± 0.1 | −2.0 ± 0.1 | −1.6 ± 0.2 |
| Km at −100 mV pH 5.6 (mM Suc) | 10.9 ± 1.4 | 7.7 ± 1.4 | 9.9 ± 0.9 | 6.9 ± 0.9 | 34.7 ± 3.8 | 13.0 ± 1.2 |
| pH dependence | The wild type | Wild-type-like | Wild-type-like | Wild-type-like | Wild-type-like | Wild-type-like |
| Pre–steady state currents (Ipre) | The wild type | Wild-type-like | − | Wild-type-like | Wild-type-like | Wild-type-like |
| Transport of sucralose | − | − | − | − | − | − |
| Inhibition by sucralose | + | + | + | + | + | + |
| Voltage-dependent fluorescence change | − | − | ++ | + | + | +++ |
−, no; +, yes; ++ or +++ indicates the intensity of fluorescence changes.