| Aspect | Finding for **P. putida KT2440 oprE / OprE** | Evidence type | Key quantitative details | Source (year; DOI/URL) |
|---|---|---|---|---|
| Identity verification | **oprE = PP_0234** in **Pseudomonas putida KT2440**; described as an **outer membrane integral porin**. This matches the requested UniProt-linked gene/protein identity. | Direct experimental study in the correct organism | Constructs included **KT-oprE**, **KT-oprFE**, **KTΔmscL-oprFE** with cloned **oprE (PP_0234)** (pqac-00000003, pqac-00000010) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Subcellular localization | OprE is localized to the **outer membrane**; it is also detected among proteins in **outer membrane vesicles (OMVs)** from KT2440. | Direct for OM/OMV association | OMV proteomics identified OprE among major OMV protein components; no OprE-specific abundance values in excerpt (pqac-00000004) | Choi et al., 2014; https://doi.org/10.1021/pr500411d |
| Functional class | OprE is treated as a **porin**; broader Pseudomonas literature places OprE within the **OprD-family / substrate-selective outer membrane porins**. | Mixed: direct porin annotation in KT2440; family assignment inferred from homologous Pseudomonas literature | No KT2440 transport assay reported in retrieved evidence (pqac-00000002, pqac-00000003) | Tamber et al., 2006; https://doi.org/10.1128/JB.188.1.45-54.2006; Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Regulation: anaerobiosis | OprE is reported as normally produced under **anoxygenic/anaerobic conditions** in other Pseudomonas strains; this is used as contextual functional annotation for KT2440 OprE. | Indirect/background inference, not a KT2440-specific induction experiment in retrieved evidence | No fold induction for KT2440 in retrieved evidence (pqac-00000001, pqac-00000003) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Regulation: nutrient status | In KT2440, OprE is **hunger-repressed**: OprE abundance decreases under glucose limitation relative to richer glucose conditions. | Direct experimental proteomics in KT2440 | ~**50 kDa** OprE band in OM fractions was distinct at **0.4% or 0.8% glucose** and barely detectable at **0.2% glucose**; no fold-change provided (pqac-00000005) | Putrinš et al., 2011; https://doi.org/10.1186/1471-2180-11-170 |
| Inferred substrate specificity | Specific substrate for **P. putida PP_0234** is **not directly demonstrated** in retrieved KT2440 studies. From **P. aeruginosa** OprD-family literature, OprE is **predicted** to transport **arginine or proline**; additional tested compounds in ortholog work include sodium pantothenate, uracil, pyroglutamate, and p-aminobenzoic acid. | **Inference from another species**; should not be treated as proven for KT2440 PP_0234 | Growth/substrate testing was reported for the **P. aeruginosa** ortholog context, not directly for KT2440 PP_0234 (pqac-00000000, pqac-00000002) | Tamber et al., 2006; https://doi.org/10.1128/JB.188.1.45-54.2006; Tamber, 2010 thesis; https://doi.org/10.14288/1.0093018 |
| Role in engineered cell-envelope permeability | Overexpressed OprE, especially with OprF, was used to increase outer membrane permeability/hydrophobicity in KT2440 for downstream bioprocessing. | Direct experimental engineering study | Porin-bearing strains showed **>3-fold** increased membrane hydrophobicity; KT-oprFE showed **21% membrane disturbance**; permeability changes supported by NPN uptake (pqac-00000007, pqac-00000009, pqac-00000015) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Growth and biomass effects of oprE engineering | **Single porin overexpression** (including OprE alone) did **not impair growth rate, final biomass, or PHA yield** under PHA-producing conditions; dual OprF/OprE expression had a modest biomass cost. | Direct experimental evidence in KT2440 | After **48 h**, individual porin overexpression caused no impairment; dual OprF/OprE in **KTΔmscL-oprFE** caused about **10% biomass reduction** but higher PHA content as % CDM (pqac-00000001, pqac-00000006, pqac-00000008, pqac-00000011) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Autolysis/cell disruption performance | Combining **mscL deletion** with **OprF/OprE overexpression** enabled efficient osmotic-shock-driven cell disruption for intracellular product recovery. | Direct experimental evidence in KT2440 | Hypertonic step followed by hypotonic shock gave **>95%** disruption within **3 h**; reported values include **96.3% cell disruption/death** and viability losses of **20%, 80%, 96%** after **1, 2, 3 h** respectively (pqac-00000006, pqac-00000010, pqac-00000014, pqac-00000015) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Process conditions used in the key engineering study | OprE/OprF overexpression was induced during PHA production on decanoate; disruption relied on controlled osmotic transitions. | Direct experimental protocol | Growth on **20 mM decanoate**; porin expression induced with **1 mM IPTG at 30 h** for **18 h**; hypertonic step included **10 g/L NaCl**, then transfer to distilled water for hypotonic shock (pqac-00000003, pqac-00000012, pqac-00000014) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| Product recovery relevance | OprE participates in a real-world biotechnology implementation for **PHA recovery** from KT2440 by reducing downstream disruption burden. | Direct applied bioprocess evidence | Reported PHA recovery values were **94.2%**, **~94%**, or **93.3%** depending on excerpted section; monomer composition reportedly unchanged (pqac-00000006, pqac-00000008, pqac-00000012, pqac-00000014) | Poblete-Castro et al., 2020; https://doi.org/10.3389/fbioe.2020.00161 |
| 2023–2024 perspective | Recent reviews cite the OprF/OprE + **mscL** strategy as an example of **engineered autolysis / improved PHA recovery** in Pseudomonas. | Review-level synthesis | 2023 review confirms concurrent OprF/OprE overproduction with **mscL** deletion as an osmotic-imbalance strategy; 2024 autolysis review discusses this KT2440 system as a programmable cell disruption example (pqac-00000016, pqac-00000006) | Acuña & Poblete-Castro, 2023; https://doi.org/10.1111/1751-7915.14109; Dong et al., 2024; https://doi.org/10.1186/s12934-024-02566-z |


*Table: This table summarizes verified evidence for Pseudomonas putida KT2440 OprE/oprE (PP_0234; UniProt Q88R99), separating direct KT2440 findings from cross-species inference. It highlights localization, regulation, inferred substrate specificity, and the strongest quantitative data from the 2020 engineered cell-disruption study.*