Gene Description

GalU (PP_3821) is the predicted UTP:glucose-1-phosphate uridylyltransferase of Pseudomonas putida KT2440. It reversibly forms UDP-alpha-D-glucose and diphosphate from glucose 1-phosphate and UTP, supplying a nucleotide-sugar branch point used by multiple envelope and carbohydrate pathways, including lipopolysaccharide, exopolysaccharide, and alpha-glucan metabolism.

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0003983 UTP:glucose-1-phosphate uridylyltransferase activity	IEA GO_REF:0000120	ACCEPT	Summary: This term exactly represents the predicted GalU reaction. Reason: Q88GA4 carries EC 2.7.7.9/RHEA:19889, the bacterial GalU family signature, and the matching substrate-specific GO annotation. Supporting Evidence: file:PSEPK/galU/galU-uniprot.txt DR GO; GO:0003983; F:UTP:glucose-1-phosphate uridylyltransferase activity; IEA:UniProtKB-EC.
GO:0006011 UDP-alpha-D-glucose metabolic process	IEA GO_REF:0000002	ACCEPT	Summary: GalU directly forms and consumes UDP-alpha-D-glucose. Reason: UDP-alpha-D-glucose is a direct product in the assigned reversible RHEA:19889 reaction. This process annotation does not restrict the metabolite to glycogen or any one downstream pathway. Supporting Evidence: file:PSEPK/galU/galU-uniprot.txt Reaction=alpha-D-glucose 1-phosphate + UTP + H(+) = UDP-alpha-D-glucose

Core Functions

Reversibly forms UDP-alpha-D-glucose from alpha-D-glucose 1-phosphate and UTP, supplying a nucleotide-sugar branch point for carbohydrate and envelope metabolism.

Molecular Function:

UTP:glucose-1-phosphate uridylyltransferase activity

Directly Involved In:

UDP-alpha-D-glucose metabolic process

Supporting Evidence:

file:PSEPK/galU/galU-uniprot.txt
Reaction=alpha-D-glucose 1-phosphate + UTP + H(+) = UDP-alpha-D-glucose

References

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Suggested Experiments

Experiment: Combine galU depletion or conditional knockdown with nucleotide-sugar metabolomics, Q88FN9 donor assays, and alpha-glucan quantification to test the proposed GalU-to-GlgA connection.

Deep Research

OpenScientist

(galU-deep-research-openscientist.md)

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📚 Additional Documentation

Notes

(galU-notes.md)

galU curation notes

Q88GA4 is predicted to catalyze EC 2.7.7.9/RHEA:19889, forming UDP-alpha-D-glucose from glucose 1-phosphate and UTP. [file:PSEPK/galU/galU-uniprot.txt, "Reaction=alpha-D-glucose 1-phosphate + UTP + H(+) = UDP-alpha-D-glucose"]
The imported stationary-phase-survival comment is not used as a core function because it is an ARBA prediction and does not identify a direct molecular role.
PAO1 contains GalU but lacks GlgC, and purified PAO1 GlgA preferentially uses UDP-glucose. [PMID:33872310, "Although PAO1 also contains genes for the phosphoglucomutase PgmA and the UDP-glucose pyrophosphorylase GalU, the ADP-glucose phosphorylase gene glgC is not present."]
KT2440 has the same GalU-positive, GlgC-negative architecture. This makes Q88GA4 the leading donor-supply candidate for Q88FN9, but the connection remains an inference until direct KT2440 flux or biochemical evidence is available.

galU