Table 1 Templates used to interrogate shikimic acid pathway structure in the sequenced genomes of prokaryotes.
Shikimate Pathway Step | Product | Enzymes and Enzyme Isoforms | Source and Genetic/Protein Templates |
|---|---|---|---|
1 | 3-Deoxy-D-arabino-heptulosinate -7- phosphate (DAHP) | DAHP synthase EC 4.1.2.15 (aroF), (aroG), (aroH) | In E. coli there are three DAHP synthetase isoforms, each specifically inhibited by one of the three aromatic amino acids. |
KDPGal aldolase EC 4.1.2.21 | See: http://www.brenda-enzymes.org/php/result_flat.php4?ecno=4.1.2.21 and [12] | ||
2 | 3-Dehydroquinate (DHQ) | DHQ synthase EC 4.2.3.4 (aroB) | DHQ synthase exists as type 1 and 2 enzymes (previously EC 4.6.1.3) |
3 | 3-dehydroshikimate (DHS) | Shikimate dehydrase EC 4.2.1.10 (aroD) | shikimate dehydrase and shikimate dehydrogenase are often a bifunctional enzyme |
4 | Shikimic acid (shikimate) | Shikimate dehydrogenase EC 1.1.1.25 (aroE) | E. coli has the putative enzyme YdiB paralog [25] |
5 | Shikimate-3-phosphate | Shikimate kinase II EC 2.7.1.71 (aroL) | monofunctional shikimate kinase |
Archaeal GHMP shikimate kinase | See: http://www.wikiproteins.org/index.php/Concept:62865969 and [11] | ||
6 | 5-Enolpyruvyl-shikimate-3-phosphate (EPSP) | EPSP Synthase EC 2.5.1.19 (aroA) | The AroA gene, coding for the E. coli EPSP synthase, was first isolated from a lambda transducing phage (lambda-serC) found to contain a portion of the E. coli chromosome |
2-6 | 5-Enolpyruvyl-shikimate-3-phosphate (EPSP) | Shikimate kinase I EC 4.2.3.4 EC 4.2.1.10 EC 1.1.1.25 EC 2.7.1.71 EC 2.5.1.19 (aroM) | Pentafunctional gene consisting of aroB, aroD, aroE, aroL and aroA |
7 | Chorismic acid (chorismate) | Chorismate synthesis EC 4.2.3.5 (aroC) | previously EC 4.6.1.4 Chorismate synthase from various sources shows a high degree of sequence conservation. |