algF

UniProt ID: Q88ND4
Organism: Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440)
Review Status: DRAFT
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Gene Description

AlgF is a noncatalytic periplasmic component of the AlgI-AlgJ-AlgF alginate O-acetylation complex. It is required for O-acetylation and also couples the modification machinery to the Alg8-containing polymerization and secretion complex, with AlgF loss impairing alginate production in Pseudomonas.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0042121 alginic acid biosynthetic process
IEA
GO_REF:0000120 		ACCEPT
Summary: AlgF contributes both to O-acetylation and to stable coupling with the alginate polymerization machinery.
Reason: GO:0051979 is not an ontology descendant of GO:0042121, so replacing this row would lose the broader biosynthesis role. The AlgF-specific deletion impairs alginate production, and AlgF stability is coupled to Alg8, supporting retention of the parent process while acetylation is added as a separate exact annotation.
Supporting Evidence:
PMID:31900562
only the AlgF deletion impaired alginate production
PMID:31900562
AlgI and AlgF stability was strongly impaired supporting a link of the O-acetylation machinery with alginate polymerisation.
GO:0051979 alginic acid acetylation
ISS
PMID:12003941
Mutant analysis and cellular localization of the AlgI, AlgJ,... 		NEW
Summary: AlgF is required for the periplasmic alginate O-acetylation machinery.
Reason: Nonpolar deletion and complementation establish the role of the P. aeruginosa ortholog, while Q88ND4 retains the exact AlgF family and syntenic position in the KT2440 alginate operon.
Supporting Evidence:
PMID:12003941
each mutant produced alginate lacking O-acetyl groups.
GO:0042597 periplasmic space
IEA
GO_REF:0000044 		ACCEPT
Summary: The periplasmic-space annotation is correct for AlgF.
Reason: AlgF acts as a periplasmic component of the alginate modification machinery, so this location is part of its core biological role.
Supporting Evidence:
file:PSEPK/algF/algF-uniprot.txt
SUBCELLULAR LOCATION: Periplasm
file:PSEPK/algF/algF-goa.tsv
GO:0042597 periplasmic space
file:PSEPK/algF/algF-deep-research-falcon.md
The same pathway model describes **AlgF as a periplasmic protein**, with AlgI and AlgJ being membrane-associated components
file:PSEPK/algF/algF-deep-research-falcon.md
Acetylation and epimerization steps take place in the periplasm under the concerted action of AlgI, AlgJ and AlgF for O-acetylation

Core Functions

Noncatalytic periplasmic AlgI-AlgJ-AlgF complex component required for alginate O-acetylation and coupled to Alg8-dependent polymer production.

Directly Involved In:
alginic acid acetylation alginic acid biosynthetic process
Cellular Locations:
periplasmic space
Supporting Evidence:

References

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Suggested Questions for Experts

Q: Which component of the AlgF/AlgI/AlgJ machinery carries the catalytic acetyltransferase step in KT2440?

Suggested Experiments

Experiment: Compare alginate acetylation profiles in algF, algI, and algJ knockout strains and complement each deletion with tagged proteins.

Type: alginate modification profiling

Deep Research

Falcon

(algF-deep-research-falcon.md)

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📚 Additional Documentation

Notes

(algF-notes.md)

algF curation notes

  • P. aeruginosa nonpolar algF deletion produces non-acetylated alginate and is
    rescued by complementation [PMID:12003941, "each mutant produced alginate
    lacking O-acetyl groups"].
  • Unlike algI or algJ deletion, AlgF deletion also impairs alginate production,
    and AlgF stability depends on the polymerase context [PMID:31900562, "only
    the AlgF deletion impaired alginate production"].
  • GO:0051979 is not a descendant of GO:0042121. The review therefore retains
    alginic acid biosynthetic process and adds alginic acid acetylation
    separately.
  • No direct catalytic activity is established for AlgF; it remains a
    noncatalytic accessory component rather than receiving an invented molecular
    function.

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