outer membrane-bounded periplasmic space

GO:0030288 · Envelope · Subcellular region · Proposed

The region between the inner (cytoplasmic or plasma) membrane and outer membrane of organisms with two membranes such as Gram negative bacteria. These periplasmic spaces are relatively thick and contain a thin peptidoglycan layer (PGL), also referred to as a thin cell wall. [GO:0030288]

Synonyms: outer membrane bounded periplasmic space; outer membrane-enclosed periplasmic space

Has part: Gram-negative-bacterium-type cell wall (GO:0009276)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
Gram-negative-bacterium-type cell wall	Peptidoglycan	part of	`GO:0009276`			UNKNOWN	Thin peptidoglycan sacculus that lies within the periplasm and is tethered to the outer membrane by lipoprotein links in canonical Gram-negative envelopes. `GO:0030288` GO:0030288 notes that the outer membrane-bounded periplasmic space contains a thin peptidoglycan layer. `DOI:10.1101/cshperspect.a000414` Silhavy, Kahne and Walker 2010 describe the Gram-negative envelope as an outer membrane surrounding a thin peptidoglycan wall in the periplasm.

Taxonomic distribution

NCBITaxon:2 Bacteria — VARIABLE: The outer membrane-bounded periplasm occurs in diderm bacteria; monoderm bacteria lack an outer membrane and therefore lack this specific periplasmic space. [DOI:10.1101/cshperspect.a000414]

Canonical examples

NCBITaxon:562 Escherichia coli — Canonical Gram-negative model for the outer membrane-bounded periplasm and for Lpt-dependent transport through the periplasm. [DOI:10.1101/cshperspect.a000414]

Functions

diderm envelope compartmentalization — The outer membrane-bounded periplasm separates the cytoplasmic and outer membranes while housing the thin peptidoglycan layer.
- GO:0030288 GO:0030288 defines the diderm periplasm by its position between the inner and outer membranes.
outer membrane biogenesis — Envelope assembly pathways use periplasm-spanning transport and periplasmic intermediates to deliver lipopolysaccharide and proteins to the outer membrane.
- DOI:10.1101/cshperspect.a000414 Silhavy, Kahne and Walker 2010 review Gram-negative outer-membrane biogenesis as an envelope-spanning process.
- DOI:10.1074/jbc.R117.802512 Sperandeo, Martorana and Polissi 2017 review LPS transport from the inner membrane across the periplasm to the outer membrane.

Mechanism graphs

Inner and outer membranes bound the Gram-negative periplasm (FUNCTION)

The plasma membrane and cell outer membrane delimit the diderm periplasmic region, which contains the thin Gram-negative peptidoglycan wall and is crossed by LPS transport machinery during outer-membrane assembly.

Subject	Predicate	Object	Evidence
plasma membrane	bounds the inner side of	outer membrane-bounded periplasmic space	`GO:0030288` GO:0030288 defines this periplasmic space as the region between the inner and outer membranes.
cell outer membrane	bounds the outer side of	outer membrane-bounded periplasmic space	`GO:0030288` GO:0030288 defines this periplasmic space as the region enclosed by the inner and outer membranes.
Gram-negative-bacterium-type cell wall	resides in	outer membrane-bounded periplasmic space	`DOI:10.1101/cshperspect.a000414` Silhavy, Kahne and Walker 2010 describe the Gram-negative envelope as a thin peptidoglycan wall surrounded by an outer membrane.
Lpt lipopolysaccharide transport machinery	moves across	outer membrane-bounded periplasmic space	`DOI:10.1074/jbc.R117.802512` Sperandeo, Martorana and Polissi 2017 review LPS transport across the Gram-negative envelope and through the periplasm.
Lpt lipopolysaccharide transport machinery	delivers	lipopolysaccharide	`DOI:10.1074/jbc.R117.802512` Sperandeo, Martorana and Polissi 2017 review the Lpt pathway as the Gram-negative LPS transport system.
lipopolysaccharide	is inserted into	cell outer membrane	`DOI:10.1074/jbc.R117.802512` Sperandeo, Martorana and Polissi 2017 review LPS delivery to the outer membrane by the Lpt pathway.

Discussions

INTERPRETATION (RESOLVED): Keep the outer membrane-bounded periplasmic space separate from the Gram-negative-bacterium-type cell wall record. GO:0030288 denotes the entire region between the inner and outer membranes, whereas GO:0009276 denotes the thin peptidoglycan wall located inside that region.
INTERPRETATION (RESOLVED): Keep the inner and outer membranes as boundaries of the outer membrane-bounded periplasmic space rather than as periplasm components. GO:0030288 denotes the region between the inner and outer membranes, so those membranes bound the region but are not contained by it.

Evidence

GO:0030288 Gene Ontology cellular-component term for the outer membrane-bounded periplasmic space.
GO:0042597 Gene Ontology cellular-component term for periplasmic space.
GO:0005886 Gene Ontology cellular-component term for plasma membrane.
GO:0009276 Gene Ontology cellular-component term for the Gram-negative-bacterium-type cell wall.
GO:0009279 Gene Ontology cellular-component term for cell outer membrane.
DOI:10.1101/cshperspect.a000414 Silhavy, Kahne and Walker 2010, The Bacterial Cell Envelope, Cold Spring Harbor Perspectives in Biology.
DOI:10.1074/jbc.R117.802512 Sperandeo, Martorana and Polissi 2017, The lipopolysaccharide transport (Lpt) machinery, Journal of Biological Chemistry.

Curation history

2026-09-12T04:02:43Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T04:03:27Z codex · EXPANDED_RECORD — Added GO exact synonyms, periplasmic-space parentage, the contained Gram-negative cell-wall part, inner/peptidoglycan/outer envelope components, bacterial distribution, an E. coli canonical example, diderm compartment and outer-membrane biogenesis functions, literature evidence, a nonmechanistic Lpt topology graph, and a resolved periplasm-versus-wall boundary discussion.
2026-09-12T04:11:50Z codex · ADDRESSED_PR_REVIEW — Addressed PR #576 review issues #577 and #578 by removing periplasm boundary membranes from components and adding an LPS-to-outer-membrane topology edge.

Source: data/structures/envelope/outer_membrane_bounded_periplasmic_space.yaml