Osmoregulated periplasmic glucan biosynthesis

A species-neutral Gram-negative bacterial module for osmoregulated periplasmic glucan backbone biosynthesis by an OpgH inner-membrane glucosyltransferase and an OpgG/OpgD-family periplasmic glucan-processing partner. Pseudomonas putida KT2440 provides the current UniProt exemplars, but accessory OPG decoration and unrelated cyclic-glucan routes remain outside the module boundary.

MODULE:osmoregulated_periplasmic_glucan_biosynthesisDRAFTBiological Processmodules/osmoregulated_periplasmic_glucan_biosynthesis.yaml
osmoregulated periplasmic glucan biosynthetic processGO:1900727
UniPathway:UPA00637
UniPathway UPA00637
The local UPA00637 membership set contains opgH and opgG as the two KT2440 primary genes for osmoregulated periplasmic glucan biosynthesis.
GO:1900727
osmoregulated periplasmic glucan biosynthetic process
GO:1900727 is the specific GO biological-process term for formation of osmoregulated periplasmic glucan and is more precise than generic glucan or carbohydrate biosynthetic-process terms.
PMID:37735577
Identification of enzymatic functions of osmo-regulated periplasmic glucan biosynthesis proteins from Escherichia coli reveals a novel glycoside hydrolase family.
Primary biochemical and structural analysis of E. coli OpgG/OpgD showed OpgG beta-1,2-glucanase activity and established the GH186 family, grounding ISS transfer of GO:0033913 to P. putida OpgG.
PMID:17906125
Linear osmoregulated periplasmic glucans are encoded by the opgGH locus of Pseudomonas aeruginosa.
Closely related P. aeruginosa opgGH produces linear beta-1,2-linked OPGs and provides the nearest Pseudomonas pathway context for KT2440 opgG/opgH.
PMID:15313617
Structural analysis of Escherichia coli OpgG, a protein required for the biosynthesis of osmoregulated periplasmic glucans.
The E. coli OpgG structure identified a carbohydrate-related beta-sandwich domain with an aromatic/acidic cleft, supporting the catalytic-family context later resolved by GH186 biochemical work.
file:PSEPK/opgH/opgH-ai-review.yaml
Curated opgH review
The opgH review accepts inner-membrane localization and modifies broad glucan biosynthesis and hexosyltransferase annotations to OPG biosynthesis and glucosyltransferase activity.
file:PSEPK/opgH/opgH-deep-research-openscientist.md
OpenScientist gene research for opgH
OpenScientist supports OpgH as a UDP-glucose-dependent inner-membrane GT2/OpgH-family glucosyltransferase for OPG backbone synthesis and flags FtsZ moonlighting as untested in KT2440.
file:PSEPK/opgG/opgG-ai-review.yaml
Curated opgG review
The opgG review keeps carbohydrate binding as non-core, identifies beta-1,2-glucanase activity as the core molecular function, and accepts Gram-negative periplasmic localization while modifying broad carbohydrate/glucan process terms to OPG biosynthesis.
file:PSEPK/opgG/opgG-deep-research-openscientist.md
OpenScientist gene research for opgG
OpenScientist integrates the primary OpgG/OpgD literature with sequence conservation and opgGH operon context for P. putida OpgG.
file:modules/osmoregulated_periplasmic_glucan_biosynthesis-deep-research-openscientist.md
OpenScientist module research for osmoregulated periplasmic glucan biosynthesis
OpenScientist module-level research supports UPA00637 as the conserved OpgH/OpgG OPG-backbone module and separates it from OPG decoration, Ndv/Chv cyclic-glucan routes, and the distinct BcsA-like cyclic beta-1,3-glucan system.
file:projects/P_PUTIDA/deep-research/PSEPK__osmoregulated_periplasmic_glucan_biosynthesis__upa00637-deep-research-openscientist.md
OpenScientist species-aware pathway research for PSEPK UPA00637
OpenScientist species-aware research supports UPA00637 as a covered KT2440 backbone module with adjacent opgH and opgG, while keeping accessory OPG tailoring genes outside this module's scope.

Reusable boundary: this module covers the conserved OpgH/OpgG backbone system for osmoregulated periplasmic glucan biosynthesis, not OPG decoration, Ndv/Chv cyclic-glucan routes, or the distinct BcsA-like cyclic beta-1,3-glucan system. The PSEPK instantiation is satisfiable with opgH/Q88D04 as the multi-pass inner-membrane glucosyltransferase exemplar and opgG/Q88D03 as the Sec-exported OpgD/OpgG-family periplasmic processing exemplar. Direct KT2440 biochemical evidence and the exact division of labor between OpgH and OpgG remain follow-up questions.

3Nodes
2Parts
0Variant Sets
0Variants
2Annotons
0Connections

Derived QC

Recommended-field compliance

60.0% recommended fields populated
  • module.knowledge_gaps[0] · status (0/1)
  • module.knowledge_gaps[0] · provenance (0/1)

Module deep research

✓ present

  • osmoregulated_periplasmic_glucan_biosynthesis-deep-research-openscientist.md (openscientist)

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Gene-review completeness (2/2 grounded genes reviewed)

2 complete review(s) · 2 with deep research · 0 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
opgG Q88D03 ✓ ✓ ✓
opgH Q88D04 ✓ ✓ ✓

Details

Osmoregulated periplasmic glucan biosynthesisBiological Processosmoregulated_periplasmic_glucan_biosynthesis
osmoregulated periplasmic glucan biosynthetic processGO:1900727
Part 1: Inner-membrane OPG glucosyltransferase
OpgH glucosyltransferase stepReactionopgH_opg_glucosyltransferase_step

OpgH is the multi-pass inner-membrane glycosyltransferase 2-family protein that uses UDP-glucose to supply glucosyltransferase activity for OPG backbone biosynthesis.

Annotons

opgH: OPG glucosyltransferase
opgH_glucosyltransferase
Participant: Family: OpgH glucan biosynthesis glucosyltransferase family
Family:
OpgH glucan biosynthesis glucosyltransferase familyInterPro:IPR023725
Representative Members: PSEPK opgH exemplarUniProtKB:Q88D04

Function

glucosyltransferase activityGO:0046527

Processes

osmoregulated periplasmic glucan biosynthetic processGO:1900727

Locations

plasma membraneGO:0005886

Inner-membrane glucosyltransferase component that builds the OPG backbone from UDP-glucose.

Part 2: Periplasmic OPG biosynthesis protein
OpgG periplasmic glucan biosynthesis stepBiological ProcessopgG_periplasmic_glucan_biosynthesis_step

OpgG is a signal-peptide-bearing periplasmic OpgD/OpgG-family protein associated with OPG biosynthesis and beta-1,2-glucan backbone processing.

Annotons

opgG: periplasmic OPG biosynthesis factor
opgG_glucan_biosynthesis_factor
Participant: Family: OpgD/OpgG glucan biosynthesis family
Family:
OpgD/OpgG glucan biosynthesis familyInterPro:IPR023704
Representative Members: PSEPK opgG exemplarUniProtKB:Q88D03

Function

glucan endo-1,2-beta-glucosidase activityGO:0033913

Processes

osmoregulated periplasmic glucan biosynthetic processGO:1900727

Locations

outer membrane-bounded periplasmic spaceGO:0030288

Periplasmic beta-1,2-glucanase that likely processes the OPG backbone during glucan maturation.