oprE

Gene Description

OprE (PP_0234) is an outer membrane porin of Pseudomonas putida KT2440 belonging to the OprD/Occ (Opr) family of substrate-selective porins (TC 1.B.25; Pfam OprD, PF03573). Like other members of this family, it forms a beta-barrel channel embedded in the Gram-negative outer membrane that allows the selective diffusion of small hydrophilic solutes across the outer membrane permeability barrier. The mature protein (residues 22-444, following cleavage of an N-terminal signal peptide) localizes to the outer membrane and is also recovered in outer membrane vesicles. In Pseudomonas, OprE-family porins are typically substrate-selective, semi-specialized nutrient-uptake channels whose expression responds to environmental conditions; the OprE ortholog is classically described as anaerobically induced, and in P. putida OprE abundance varies with nutrient (glucose) availability. The precise substrate specificity of P. putida KT2440 OprE has not been established by direct transport assays; substrate predictions (e.g. basic amino acids) derive from the P. aeruginosa OprD-family framework and remain hypotheses for this ortholog.

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0015288 porin activity	IEA GO_REF:0000120	ACCEPT	Summary: Correctly captures the core molecular function of OprE as an outer membrane porin (beta-barrel channel allowing diffusion of solutes across the outer membrane). This is well supported by family/domain membership (OprD/Opr family, Pfam OprD) and by experimental treatment of OprE as an outer membrane porin in KT2440. Reason: Porin activity is the defining function of the OprD/Occ-family proteins and is consistent with the InterPro/PANTHER-based inference and with literature describing OprE as an outer membrane integral porin in P. putida KT2440.
GO:0016020 membrane	IEA GO_REF:0000002	MODIFY	Summary: OprE is a membrane protein, but the available evidence supports the more specific localization to the bacterial outer membrane rather than the generic membrane term. OprE is described as an outer membrane integral porin in KT2440 and is recovered in outer membrane vesicles. Reason: The generic membrane term (GO:0016020) is correct but uninformatively broad for a Gram-negative outer membrane porin. The OprD/Occ family is an outer membrane beta-barrel family, and OprE is experimentally and proteomically associated with the outer membrane, justifying refinement to the outer membrane term. Proposed replacements: outer membrane
GO:0055085 transmembrane transport	IEA GO_REF:0000108	ACCEPT	Summary: Consistent with the porin function. As a porin, OprE mediates the diffusion of solutes across the outer membrane, so participation in transmembrane transport is appropriate. This term was logically inferred from the porin activity annotation (GO:0015288). Reason: Transmembrane transport is the biological process directly entailed by porin (channel) activity and is well supported as the process counterpart to the molecular function annotation.

Core Functions

Outer membrane porin (beta-barrel channel) of the OprD/Occ family that mediates selective diffusion of small hydrophilic solutes across the Gram-negative outer membrane, contributing to transmembrane transport at the cell envelope.

Molecular Function:

porin activity

Directly Involved In:

transmembrane transport

Cellular Locations:

outer membrane

Supporting Evidence:

PMID:32211393
The second channel taken into analysis was the outer membrane integral porin OprE (PP_0234), which is normally produced under anoxygenic conditions in other Pseudomonas strains

Gene Description

Existing Annotations Review

Core Functions

Outer membrane porin (beta-barrel channel) of the OprD/Occ family that mediates selective diffusion of small hydrophilic solutes across the Gram-negative outer membrane, contributing to transmembrane transport at the cell envelope.

References

Deep Research

Falcon

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