OprE (OccK8, PA0291) is an anaerobically induced outer membrane channel of Pseudomonas aeruginosa belonging to the OccK subfamily of the outer membrane carboxylate channel (Occ, formerly OprD) family. It is a beta-barrel substrate-specific channel with a Sec signal peptide; purified native OccK8 forms channels in planar lipid bilayers with several conductance states, and its permeation of charged amino acids has been probed. It was originally identified as outer membrane protein E1, whose reduced level was associated with decreased outer membrane permeability to beta-lactams and quinolones. Its physiological substrates are not established.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0015288 porin activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN002160747 (seeds OprD, OpdP and this gene). Reason: Sound: the IBD rests on OprD; OprE is a member of the same Occ channel clade and has its own single-channel evidence. Supporting Evidence: PMID:33481046 OccK8 (also known as OprE), was investigated using single-channel |
| GO:0015288 porin activity | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO porin activity from the OprD family signature. Reason: Consistent with channel recordings. Supporting Evidence: PMID:33481046 OccK8 (also known as OprE), was investigated using single-channel |
| GO:0015288 porin activity | IMP PMID:2120174 Outer membrane proteins responsible for the penetration of b... | ACCEPT | Summary: PseudoCAP IMP porin activity, the seed row of PTN002160747 for this gene. The abstract reports mutants that lost four OM proteins (C, D2, E1, E2) together and concludes only that at least one of them is a porin. Reason: The claim is correct (OccK8/OprE forms channels in bilayers), so the row stays consistent with the other porin rows, but the cited evidence cannot attribute porin activity to OprE; recorded as a PseudoCAP CHECK defect. Supporting Evidence: PMID:33481046 OccK8 (also known as OprE), was investigated using single-channel PMID:2120174 decreased amounts of outer membrane proteins C, D2, E1, and E2 lowered the |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: Membrane from InterPro. Reason: Correct but general; OprE is an outer membrane beta-barrel channel, so cell outer membrane (GO:0009279). Proposed replacements: cell outer membrane Supporting Evidence: PMID:2120174 decreased amounts of outer membrane proteins C, D2, E1, and E2 lowered the |
| GO:0019867 outer membrane | IDA PMID:2120174 Outer membrane proteins responsible for the penetration of b... | MODIFY | Summary: PseudoCAP IDA outer membrane from OM-protein profiles (protein E1). Reason: Location is right, but for a Gram-negative bacterium the specific term is cell outer membrane (GO:0009279), a descendant. Proposed replacements: cell outer membrane Supporting Evidence: PMID:2120174 decreased amounts of outer membrane proteins C, D2, E1, and E2 lowered the |
| GO:0055085 transmembrane transport | IEA GO_REF:0000108 | ACCEPT | Summary: Transmembrane transport inferred from porin activity. Reason: As precise as the evidence allows: OprE is a channel, but its physiological substrates are not established. Supporting Evidence: PMID:33481046 OccK8 (also known as OprE), was investigated using single-channel |
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Download this section (compressed HTML)Q: What are the physiological substrates of OprE/OccK8, and why is it induced under anaerobic conditions?
Experiment: Screen radiolabelled carboxylates and amino acids for OccK8-dependent uptake in porin-deficient E. coli vesicles, and compare growth of an oprE deletion on candidate carbon sources under anaerobic denitrifying conditions.
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