Table 2.
Single-turnover rates of methylation by TrmA wild-type and variants. Rates were determined by fitting duplicates of tritium release time courses with a single exponential function (Figure 3)
| TrmA variant | rate, min−1 |
|---|---|
| Wild-type (wt)a | 5.4 ± 0.6 |
| C324A | Not active |
| E358Q | Not active |
| Q190A | 1.33 ± 0.09 |
| G220D | 0.11 ± 0.01 |
| R51A | 1.28 ± 0.13 |
| R51A C324A | Not active |
| F106A | 0.23 ± 0.01 |
| F106A C324A | Not active |
| F106E | Not active |
| H125A | 0.30 ± 0.02 |
| H125A C324A | Not active |
| H125E | Not active |
aRate determined by rapid quench-flow analysis (Figure 3A).