TABLE 2.
Binding affinities of aminoglycoside resistance 16S rRNA (m7G1405) methyltransferases for SAM and SAH measured by ITC
| Class and enzyme |
Kd (μM)a |
Reference | |
|---|---|---|---|
| SAM | SAH | ||
| Acquired m7G1405 | |||
| RmtD | 42 ± 19 | 2.0 ± 0.2 | This study |
| RmtD2 | 29 ± 5b | 1.2 ± 0.3b | |
| RmtG | 11.4/10.0 | 3.7/1.0 | |
| Producer m7G1405 | |||
| Sgm | 25 ± 16b | 4.8 ± 2.6b | This study |
| Sgm | 17.6 | NDc | 17 |
| Sgm | 18 | 300 | 21 |
a
Measurements were made in triplicate with independent samples and are shown as means ± standard deviations, except for RmtG, for which only two independent measurements were made (values from both experiments are shown). Errors associated with fits to one binding site model were negligible compared to those between measurements.
b
Binding was assessed under two different solution conditions with essentially identical results.
c
ND, not determined.