Table 4.
Hydroaromatic equilibrium and intermediate levels accumulated in E. coli MG1655 harboring various shikimate modules constructed in the studya
| Module | Level (mg/liter) |
|||
|---|---|---|---|---|
| QUIN | DHQ | DHS | SHIK | |
| S0 | 106 ± 1 | 36 ± 1 | 588 ± 13 | 79 ± 2 |
| S1 | 165 ± 1 | 51 ± 1 | 1,029 ± 6 | 194 ± 2 |
| S2 | 242 ± 4 | 56 ± 1 | 1,227 ± 65 | 278 ± 28 |
| S3 | 2 ± 0 | 5 ± 0 | 70 ± 6 | 510 ± 18 |
| S4 | 3 ± 1 | 8 ± 0 | 113 ± 3 | 759 ± 39 |
| S5 | 11 ± 1 | 4 ± 0 | 46 ± 4 | 273 ± 20 |
a
Equilibrium exists between SHIK and the two preceding intermediates, DHQ and DHS, and the side product QUIN, whose formation is catalyzed by YdiB (28). It occurs immediately after the formation of DAHP and prior to the formation of shikimate 3-phosphate, the first intermediate in the tyrosine module (Fig. 1A). The hydroaromatic levels were determined under the conditions described in Table 3.