Table 3.
Additional target-site mutations in EPSPS shown to confer glyphosate resistance (increased Ki for glyphosate) with variable effects on PEP affinity (Km) when expressed in E. coli. Numbering system relative to the start of the mature EPSPS enzyme in plants, including petunia and Arabidopsis. Positions Gly101, Thr102, Pro106, Gly144 and Ala192 in plant mature EPSPS consensus correspond to Gly96, Thr97, Pro101, Gly137 and Ala183 in E. coli
| Mutation(s) | Ki(app) for glyphosate (μM) | Km (app) for PEP (μM) | Ki/Km | Reference |
|---|---|---|---|---|
| Petunia wild-type EPSPS | 0.4 | 5.2 | 0.08 | 118 |
| Gly101Ala | 2000 | 200 | 10.0 | 118 |
| Gly101Ala, Ala192Thr | 683 | 54 | 12.6 | 118 |
| Gly101Ala, Gly144Asp | 348 | 40 | 7.7 | 119 |
| Gly101Ala, Gly144Asn | 960 | 91 | 10.5 | 119 |
| Maize wild type EPSPS | 0.5 | 27 | 0.02 | 120 |
| Maize Thr102Ile | 148.6 | 233.0 | 0.6 | 120 |
| Maize Pro106Ser | 1.0 | 17.1 | 0.06 | 120 |
| Maize Thr102Ile, Pro106Ser | 58.0 | 10.6 | 5.5 | 120 |
| Maize Thr102Ile, Pro106Thr | 101.3 | 11.2 | 9.0 | 120 |
| Maize Thr102Ile, Pro106Gly | 38.6 | 23.0 | 1.68 | 120 |
| Maize Thr102Ile, Pro106Cys | 818.2 | 47.0 | 17.4 | 120 |
| Maize Thr102Ile, Pro106Ala | 148.3 | 10.2 | 14.5 | 120 |
| Maize Thr102Ile, Pro106Ile | 2500 | 60.3 | 41.5 | 120 |
| Maize Thr102Ile, Pro106Val | 1600 | 109.3 | 14.6 | 120 |
| Maize Thr102Ile, Pro106Met | 37 200 | 143.3 | 260 | 120 |
| Maize Thr102Ile, Pro106Leu | 2100 | 99.5 | 21.1 | 120 |
| Maize Pro106Thr | 4.0 | 24.6 | 0.16 | 120 |
| Maize Pro106Leu | 28.6 | 86.7 | 0.33 | 120 |
| Agrobacterium spp. CP4 | 5100 | 14.4 | 354 | 120 |