cpsG

UniProt ID: Q88LZ9
Organism: Pseudomonas putida KT2440
Review Status: DRAFT
Aliases:
PP_1777
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Gene Description

cpsG (PP_1777) encodes a ManB/CpsG-type phosphomannomutase. Its primary reaction is the magnesium-dependent interconversion of mannose 6-phosphate and mannose 1-phosphate, supplying mannose 1-phosphate for GDP-mannose and downstream cell-envelope carbohydrate biosynthesis. Direct evidence for physiologically relevant phosphoglucomutase activity is absent.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0000287 magnesium ion binding
IEA
GO_REF:0000002 		KEEP AS NON CORE
Summary: magnesium ion binding is biologically plausible for this enzyme but is ancillary to the more specific catalytic function.
Reason: Retain as a supporting/non-core annotation rather than using it as the main functional summary.
GO:0004615 phosphomannomutase activity
IEA
GO_REF:0000120 		ACCEPT
Summary: phosphomannomutase activity is consistent with the curated UniProt name, EC/family evidence, and the gene product role summarized here.
Reason: This is a specific, biologically appropriate annotation for this gene product.
GO:0005975 carbohydrate metabolic process
IEA
GO_REF:0000002 		ACCEPT
Summary: carbohydrate metabolic process is consistent with the curated UniProt name, EC/family evidence, and the gene product role summarized here.
Reason: This is a specific, biologically appropriate annotation for this gene product.
GO:0016868 intramolecular phosphotransferase activity
IEA
GO_REF:0000002 		KEEP AS NON CORE
Summary: intramolecular phosphotransferase activity is biologically plausible for this enzyme but is ancillary to the more specific catalytic function.
Reason: Retain as a supporting/non-core annotation rather than using it as the main functional summary.
GO:0009298 GDP-mannose biosynthetic process
ISS
file:PSEPK/cpsG/cpsG-deep-research-openscientist.md 		NEW
Summary: The phosphomannomutase reaction supplies mannose 1-phosphate for the canonical GDP-mannose pathway; comparative analysis supports a mannose-specialized ManB/CpsG assignment for PP_1777.
Supporting Evidence:
file:PSEPK/cpsG/cpsG-deep-research-openscientist.md
This reaction constitutes the second committed step of the GDP-mannose biosynthetic pathway

Core Functions

Phosphomannomutase (EC 5.4.2.8) interconverting mannose 6-phosphate and mannose 1-phosphate for GDP-mannose synthesis. Support is family classification only (PANTHER PTHR43771 phosphomannomutase, PROSITE PS00710 phosphoglucomutase/phosphomannomutase signature, alpha-D-phosphohexomutase Pfam domains); members of this family can also act on glucose phosphates, and no KT2440 enzyme assay is cached.

Molecular Function:
phosphomannomutase activity
Directly Involved In:
GDP-mannose biosynthetic process
Supporting Evidence:
  • file:PSEPK/cpsG/cpsG-uniprot.txt
    DR PANTHER; PTHR43771; PHOSPHOMANNOMUTASE; 1.
  • file:PSEPK/cpsG/cpsG-uniprot.txt
    DR PROSITE; PS00710; PGM_PMM; 1.
  • file:PSEPK/cpsG/cpsG-uniprot.txt
    DR InterPro; IPR005841; Alpha-D-phosphohexomutase_SF.

References

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Suggested Questions for Experts

Q: Does PP_1777 have measurable phosphoglucomutase side activity, and which GDP-mannose-derived glycans depend specifically on CpsG rather than AlgC?

Suggested Experiments

Experiment: Compare phosphomannomutase and phosphoglucomutase kinetics for purified PP_1777 and characterize nucleotide-sugar and glycan changes in a cpsG mutant.

Type: comparative enzymology and targeted genetics

Deep Research

Asta

(cpsG-deep-research-asta.md)

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OpenScientist

(cpsG-deep-research-openscientist.md)

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