Table 3. Growth characteristics of EcAmtB and ScMep2 variants.
Amt phenotype | Growth rate (OD600/hr) | |
Glutamate | NH4Cl | |
S. cerevisae wild-type | 0.175±0.005 | 0.150±0.007 |
S. cerevisae Δmep | 0.175±0.007 | 0.015±0.004 |
EcAmtB wild-type | 0.120±0.006 | 0.080±0.005 |
EcAmtB H168A | 0.145±0.008 | 0.080±0.007 |
EcAmtB H318A | 0.148±0.008 | 0.060±0.019 |
EcAmtB H168A/H318A | 0.145±0.010 | 0.015±0.001 |
EcAmtB F215A | 0.140±0.008 | 0.010±0.001 |
ScMep2 wild-type | 0.135±0.005 | 0.115±0.007 |
ScMep2 H194A | 0.165±0.012 | 0.090±0.005 |
ScMep2 H348A | 0.145±0.014 | 0.100±0.010 |
ScMep2 H194A/H348A | 0.135±0.010 | 0.015±0.002 |
S. cerevisae strains were grown in YNB liquid medium pH 6.0 with either 30 mM glutamate or 3 mM NH4Cl as the sole nitrogen source. The growth rate in logarithmic phase was recorded as OD600/hr and the data are the means of six replicate experiments. Wild-type S. cerevisae (strain 23344c) and S. cerevisae Δmep strain (31019b) were used as controls. EcAmtB and ScMep2 variants were all expressed in S. cerevisae Δmep strain (31019b).