| Feature | Key finding | Best citation IDs to support it | Source (author/year/doi URL) |
|---|---|---|---|
| Enzyme name | **trpC / PP_0422 / UniProt Q88QR6** in *Pseudomonas putida* KT2440 is assigned as **indole-3-glycerol phosphate synthase (IGPS)** based on sequence similarity to *E. coli* TrpC and placement in the tryptophan biosynthesis locus. | (pqac-00000000, pqac-00000007) | Molina-Henares et al., 2009, *Microbial Biotechnology*, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| EC number | The gene product corresponds to **EC 4.1.1.48**, the canonical IGPS carboxy-lyase in tryptophan biosynthesis. This matches the functional assignment used in comparative and pathway literature. | (pqac-00000005, pqac-00000011) | Esposito et al., 2022, *ChemBioChem*, https://doi.org/10.1002/cbic.202100314; Barona-Gómez & Hodgson, 2003, *EMBO Reports*, https://doi.org/10.1038/sj.embor.embor771 |
| Reaction | IGPS catalyzes conversion of **1-(o-carboxyphenylamino)-1-deoxyribulose-5-phosphate (CdRP)** to **indole-3-glycerol phosphate (IGP/InGP)**, the indole-ring-forming step of the pathway. | (pqac-00000005, pqac-00000009) | Esposito et al., 2022, *ChemBioChem*, https://doi.org/10.1002/cbic.202100314 |
| Substrate/product | The substrate is **CdRP** and the product is **IGP/InGP**; in the KT2440 pathway map, TrpC is explicitly positioned at the step producing indoleglycerol phosphate from the upstream anthranilate-derived intermediate. | (pqac-00000006, pqac-00000009) | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x; Esposito et al., 2022, https://doi.org/10.1002/cbic.202100314 |
| Pathway step | TrpC functions in the **tryptophan biosynthetic pathway downstream of TrpD and upstream of TrpA/TrpB**, converting the anthranilate branch intermediate into IGP before terminal tryptophan synthase steps. | (pqac-00000006, pqac-00000017) | Molina-Henares et al., 2009, *Microbial Biotechnology*, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Operon context | In KT2440, **trpC is part of the trpGDC operon**; RT-PCR showed cotranscription of **trpG-trpD-trpC**, and **trpD overlaps trpC by 6 nt**, indicating tight transcriptional/functional coupling. | (pqac-00000012, pqac-00000015) | Molina-Henares et al., 2009, *Microbial Biotechnology*, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Evidence type | Functional annotation is supported by **genome context, RT-PCR operon mapping, sequence similarity, pathway reconstruction, and mutant phenotype analysis** rather than direct biochemical characterization of the purified KT2440 enzyme. | (pqac-00000000, pqac-00000003, pqac-00000012) | Molina-Henares et al., 2009, *Microbial Biotechnology*, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Phenotype | **Loss of trpC causes tryptophan auxotrophy** in KT2440: a mini-Tn5 insertion in **PP_0422** yielded an auxotrophic mutant in the aromatic-pathway screen. | (pqac-00000002, pqac-00000014) | Molina-Henares et al., 2009, *Microbial Biotechnology*, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Applications / metabolic engineering | **Deleting trpDC (including trpC)** in KT2440 was used to block anthranilate consumption and redirect flux for product formation; the best engineered strain produced **1.54 ± 0.3 g/L (11.23 mM) anthranilate** in tryptophan-limited fed-batch culture. | (pqac-00000013) | Kuepper et al., 2015, *Frontiers in Microbiology*, https://doi.org/10.3389/fmicb.2015.01310 |
| Structure / domains | TrpC/IGPS is a **(β/α)8 TIM-barrel enzyme** with a conserved catalytic architecture. The UniProt/domain assignment for Q88QR6 is consistent with this family-level structural model, although no KT2440-specific structure was identified here. | (pqac-00000005, pqac-00000008, pqac-00000010) | Esposito et al., 2022, *ChemBioChem*, https://doi.org/10.1002/cbic.202100314; Kursula, 2003 |
| Localization | No direct KT2440 localization experiment was found in the retrieved evidence. Given its role in central amino-acid biosynthesis and lack of membrane/export features in the discussed sources, TrpC is best inferred to function in the **cytosol**. | (pqac-00000006, pqac-00000007) | Molina-Henares et al., 2009, *Microbial Biotechnology*, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Recent 2023–2024 relevance | Recent work did not directly recharacterize KT2440 TrpC, but **2024 shikimate-pathway rewiring in *P. putida*** showed that flux through chorismate-derived aromatics can reach **89% of theoretical yield**, highlighting the modern engineering context in which trpC-associated branch control remains important. | (pqac-00000019, pqac-00000024) | dos Santos et al., 2024, https://doi.org/10.21203/rs.3.rs-4761679/v1; Bruinsma et al., 2024, *bioRxiv*, https://doi.org/10.1101/2024.07.06.602327 |


*Table: This table summarizes the experimentally supported functional annotation of *Pseudomonas putida* KT2440 trpC (PP_0422; UniProt Q88QR6), including pathway role, operon context, phenotype, structural inference, and engineering relevance. It is useful as a compact evidence map for gene-function annotation.*