| Claim | Key evidence and quantitative data | Organism context | Source with year and URL |
|---|---|---|---|
| Correct gene identity and function | PP_0421 in *Pseudomonas putida* KT2440 is identified as **trpD**, encoding anthranilate phosphoribosyltransferase; Aux-3 carries a mini-Tn5 insertion at the **184th codon** of **trpD/PP0421**, linking disruption to tryptophan auxotrophy. (pqac-00000011, pqac-00000013) | **P. putida KT2440** (target gene Q88QR7 / PP_0421) | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Biochemical reaction | Anthranilate phosphoribosyltransferase **TrpD (EC 2.4.2.18)** transfers the phosphoribosyl group from **PRPP** to **anthranilate** to form **N-(5-phospho-β-D-ribosyl)-anthranilate (PRA)** plus **PPi**; this is an early committed step in tryptophan biosynthesis. (pqac-00000006, pqac-00000007) | General bacterial/archaeal TrpD framework used to interpret the *P. putida* ortholog | Hove-Jensen et al., 2017, https://doi.org/10.1128/mmbr.00040-16; Parthasarathy et al., 2018, https://doi.org/10.3389/fmolb.2018.00029 |
| Pathway role | In *P. putida*, trpD acts downstream of anthranilate formation and upstream of later indole/tryptophan steps; mutant rescue by **tryptophan and indole** is consistent with this position in the pathway. (pqac-00000012) | **P. putida KT2440** | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Operon context | **trpGDC forms an operon** in *P. putida* KT2440; **trpE** and **trpF** are monocistronic. Physical organization supports co-transcription: **trpG–trpD separated by 9 nt** and **trpD/trpC overlap by 6 nt**; RT-PCR supports a contiguous trpG-trpD-trpC transcript. (pqac-00000011, pqac-00000012, pqac-00000014, pqac-00000009) | **P. putida KT2440**; conserved organization also noted across *Pseudomonas* spp. | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Phenotype / essentiality for minimal growth | A **trpD mutant fails to grow on M9 minimal medium** and is rescued by **L-tryptophan**; in another assay, **trpD mutants grew with tryptophan and indole**. A genome-wide mutant screen likewise identified trpD as conditionally essential for minimal-medium growth. (pqac-00000012, pqac-00000015) | **P. putida KT2440** | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x; Molina-Henares et al., 2010, https://doi.org/10.1111/j.1462-2920.2010.02166.x |
| Regulatory / transcriptional context | The trpAB locus is separate and transcribed divergently from **trpI**, a repressor-like regulator; **trpGDC** is in a distinct transcriptional unit from **trpE**, indicating split pathway organization and local regulatory separation. Direct specific regulation of PP_0421 itself was not detailed beyond operon structure. (pqac-00000011, pqac-00000012, pqac-00000016) | **P. putida KT2440** with comparative pointers to fluorescent pseudomonads | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Structural/mechanistic features supporting annotation | TrpD enzymes are typically **homodimeric**, with a **two-domain fold**, **Mg2+/Mn2+**-assisted PRPP binding, and a conserved glycine-rich PRPP-binding motif; structural studies show anthranilate-binding sites/tunnel features relevant to catalysis. (pqac-00000006, pqac-00000008) | General bacterial TrpD knowledge; not demonstrated directly for *P. putida* PP_0421 in the gathered snippets | Hove-Jensen et al., 2017, https://doi.org/10.1128/mmbr.00040-16 |
| Localization | No direct subcellular localization experiment for PP_0421/TrpD in *P. putida* was reported in the gathered evidence; the evidence supports a typical intracellular biosynthetic enzyme role rather than extracellular function. (pqac-00000000, pqac-00000011) | **P. putida KT2440** | Molina-Henares et al., 2009, https://doi.org/10.1111/j.1751-7915.2008.00062.x |
| Application: anthranilate accumulation by blocking TrpD step | In engineered **E. coli**, **trpD disruption** was used to accumulate anthranilate, reaching about **4 g/L anthranilate** in **7-L fed-batch fermentation**; the study also cites prior values of **14 g/L** in another engineered *E. coli* strain and **1.5 g/L** in *P. putida* ΔtrpDC as context. (pqac-00000018, pqac-00000021) | Other bacteria (*E. coli* primary; *P. putida* cited as comparison, not PP_0421-specific functional proof) | Kim et al., 2023, https://doi.org/10.3389/fmicb.2023.1081221 |
| Application: anthranilate production via trpD translation tuning | In engineered **Corynebacterium glutamicum**, translation-efficiency modulation of **trpD** together with **aroK** improved anthranilate production; the final strain reached **5.9 g/L (43 mM) anthranilate** in bioreactor cultivation. (pqac-00000020) | Other bacteria; demonstrates practical flux-control value of the TrpD step | Mutz et al., 2024, https://doi.org/10.1111/1751-7915.14388 |
| Application: engineered TrpD variant | In **C. glutamicum**, **TrpD A162D** was reported as feedback-resistant to L-tryptophan with increased substrate affinity; strains carrying this variant produced **3.1 g/L L-tryptophan** in flask culture, and downstream pathway engineering yielded **~28.1–29.5 mg/L APRN**. (pqac-00000019) | Other bacteria; shows TrpD can be engineered to improve tryptophan-derived product formation | Putri et al., 2024, https://doi.org/10.1186/s12934-024-02424-y |
| Application: high-tryptophan production context | A 2024 review reports that co-overexpression of **trpE** and **trpD** in an *E. coli* production background yielded **45.6 g/L tryptophan**, underscoring TrpD as a relevant engineering node in industrial pathway balancing. (pqac-00000022) | Other bacteria; review-level production context rather than direct *P. putida* evidence | Ramos-Valdovinos and Martínez-Antonio, 2024, https://doi.org/10.3390/pr12112422 |


*Table: This table summarizes direct and indirect evidence for the annotation of Pseudomonas putida KT2440 trpD (UniProt Q88QR7 / PP_0421), separating strain-specific genetic evidence from broader mechanistic and application-oriented TrpD literature. It is useful for distinguishing what is experimentally shown in the target organism versus what is inferred from authoritative studies in other bacteria.*