oprB

Summary: IBA from PTN002209977, whose IBD rests solely on OprB's own PseudoCAP row. The claim is correct for OprB and the node term suits the OprB porin family; for OprB itself the substrates are known.

Reason: OprB in its own WITH/FROM marks its experimental seed and is expected. The node is a small OprB-family clade (10 leaves in 5 taxa: OprB and its PAO1 paralogs PA2291 and PA4099, four Bradyrhizobium paralogs, Synechocystis Slr1163, Xanthomonas RpfN and a Rhodopirellula "carbohydrate-selective porin"). Carbohydrate transport is a family-level property of the Pfam PF04966 OprB carbohydrate-selective porins, so the node term is appropriately general. For OprB the uptake assays support the more specific transmembrane transport terms for glucose, mannitol, fructose and glycerol (all descendants of carbohydrate transport via carbohydrate transmembrane transport); the same replacements are used for the experimental row.

Proposed replacements: D-glucose transmembrane transport mannitol transmembrane transport fructose transmembrane transport glycerol transmembrane transport

Summary: Wylie and Worobec built oprB null and overexpressing strains and measured initial uptake of glucose, mannitol, glycerol and fructose, which fell or rose accordingly, while arginine uptake was unchanged. The claim is sound and the substrates are known.

Reason: The porin conducts these sugars across the outer membrane, so OprB does the transport work. The precise processes are the substrate-specific transmembrane transport terms. The full text (Wylie and Worobec 1995, supplied by the user and read 2026-11-05) measures initial uptake of radiolabelled sugars by whole cells of an interposon oprB mutant, its complemented and overexpressing derivatives, and wild type; it reports no assay with purified OprB, and the liposome channel work it discusses is cited from earlier papers. That is a mutant phenotype, so IMP rather than IDA (see source_defects). The claim itself is sound. Earlier channel- specificity work in liposomes (PMID:2450582, not cached) is cited by UniProt for the glucose channel.

Proposed replacements: D-glucose transmembrane transport mannitol transmembrane transport fructose transmembrane transport glycerol transmembrane transport

Summary: InterPro2GO mapping from the carbohydrate-selective porin OprB family.

Reason: Correct family-level term; for OprB itself the specific substrates are known, so the same specific replacements apply as for the experimental row.

Proposed replacements: D-glucose transmembrane transport mannitol transmembrane transport fructose transmembrane transport glycerol transmembrane transport

Summary: OprB is an outer-membrane beta-barrel porin.

Reason: Signal peptide confirmed by N-terminal sequencing, transmembrane beta-strand porin architecture, and uptake data that place its action at the outer membrane.

Summary: OprB is a substrate-selective outer-membrane porin.

Reason: Porin activity is the defining MF of OprB; it forms a beta-barrel channel that facilitates diffusion of sugars across the outer membrane. GO has no carbohydrate-specific porin term, so this is as precise as GO allows.

Summary: Correct but general; the specific membrane is the cell outer membrane.

Reason: Cell outer membrane (an is_a descendant of membrane via outer membrane) is already annotated on this gene.

Proposed replacements: cell outer membrane

Summary: Inferred from porin activity; correct but uninformative.

Reason: The supported specific processes are transmembrane transport of glucose, mannitol, fructose and glycerol, all descendants of transmembrane transport.

Proposed replacements: D-glucose transmembrane transport mannitol transmembrane transport fructose transmembrane transport glycerol transmembrane transport