id: A5FJK8 gene_symbol: Fjoh_1584 product_type: PROTEIN status: COMPLETE taxon: id: NCBITaxon:376686 label: Flavobacterium johnsoniae UW101 description: Fjoh_1584 encodes the homodimeric geranylgeranylglyceryl phosphate synthase of Flavobacterium johnsoniae UW101. This group II TIM-barrel enzyme transfers a C20 geranylgeranyl group to sn-glycerol-1-phosphate to form an ether-linked glycerophosphate. The Ile90 side chain helps restrict donor-chain length; replacing it with alanine permits heptaprenyl substrate use. The physiological role and downstream fate of the native C20 product remain unresolved. existing_annotations: - term: id: GO:0000107 label: imidazoleglycerol-phosphate synthase activity evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: enables supporting_entities: - PANTHER:PTN001846602 review: action: REMOVE summary: The TreeGrafter HisF reaction is inappropriate for this characterized GGGPS. reason: GO:0000107 catalyzes the glutamine-dependent histidine-biosynthetic reaction, whereas the characterized target transfers geranylgeranyl to glycerol phosphate. PMID:24684232 identifies HisF through structural similarity, not shared catalysis; curated target FUNCTION evidence specifies GGGPS chemistry. The PTN001846602 TreeGrafter transfer across divergent TIM-barrel activities is inappropriate. This does not assert that a negative HisF assay was performed. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/PMID24684232-fulltext-scope.md supporting_text: The article identifies HisF as a structural relative, not an equivalent catalytic activity. source_defects: - defect_type: WRONG_TERM resource: PANTHER record: PANTHER:PTN001846602 asserted_value: GO:0000107 corrected_value: GO:0047294 confidence: PROBABLE explanation: The A5FJK8 GGGPS subfamily member has experimentally curated geranylgeranyl transfer and structure4JEJ. The HisF reaction is an inappropriate TreeGrafter propagation across divergent TIM-barrel activities; check the ancestral-node functional scope. Do not replace the source protein or modify the frozen GOA payload. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/PMID24684232-fulltext-scope.md supporting_text: The article identifies HisF as a structural relative, not an equivalent catalytic activity. - term: id: GO:0000287 label: magnesium ion binding evidence_type: IEA original_reference_id: GO_REF:0000120 qualifier: enables supporting_entities: - InterPro:IPR010946 - UniRule:UR000076516 review: action: ACCEPT summary: Magnesium supports the catalytic prenyl-transfer mechanism. reason: The curated HAMAP cofactor assignment and conserved Mg-binding features support magnesium as the catalytic metal. This is a mechanistic family inference, not a claim that magnesium occupancy was directly measured in this target crystal. The full 2014 study reports no magnesium density in the groupII structures and treats its position as modeled; the accepted binding function rests on catalytic-family inference, not crystal occupancy. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:COFACTOR supporting_text: Name=Mg(2+); Xref=ChEBI:CHEBI:18420; - term: id: GO:0005737 label: cytoplasm evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: located_in supporting_entities: - InterPro:IPR010946 review: action: UNDECIDED summary: The target cellular location is not independently established by the available sources. reason: Cytoplasm is compatible with the soluble TIM-barrel enzyme, but neither the publisher full text of PMID:24684232 nor the curated target record establishes native localization. Recombinant purification and structure do not locate the protein in UW101, and absence of a transmembrane segment does not settle its cellular site. Unlike B. subtilis PcrB, this target lacks an explicit cytosolic-pathway placement. UNDECIDED records unresolved localization, not failed full-text access. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:SIMILARITY supporting_text: Belongs to the GGGP/HepGP synthase family. Group II subfamily. - term: id: GO:0006650 label: glycerophospholipid metabolic process evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: involved_in supporting_entities: - InterPro:IPR010946 review: action: MODIFY summary: The supported glycerophospholipid reaction is biosynthetic. reason: The characterized transfer of geranylgeranyl to glycerol phosphate directly synthesizes an O-alkyl glycerophosphate. GO:0046474 includes that monoether product and is the supported biosynthetic descendant already carried by this gene. This refinement concerns the enzyme reaction, without inferring downstream native product processing. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: PMID:24684232 supporting_text: family enzymes catalyse the formation of an ether bond between glycerol-1-phosphate and polyprenyl diphosphates reference_section_type: ABSTRACT proposed_replacement_terms: - id: GO:0046474 label: glycerophospholipid biosynthetic process - term: id: GO:0016765 label: transferase activity, transferring alkyl or aryl (other than methyl) groups evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables supporting_entities: - InterPro:IPR008205 review: action: MODIFY summary: The prenyl-transfer activity is known at substrate-resolved specificity. reason: The curated experimental FUNCTION statement specifies transfer of geranylgeranyl from GGPP to sn-glycerol-1-phosphate. Refine the correct broad alkyl-transfer activity to the already annotated substrate-resolved descendant GO:0047294. The wild-type C20 specificity is distinguished from engineered I90A acceptance of HepPP. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: PMID:24684232 supporting_text: family enzymes catalyse the formation of an ether bond between glycerol-1-phosphate and polyprenyl diphosphates reference_section_type: ABSTRACT proposed_replacement_terms: - id: GO:0047294 label: phosphoglycerol geranylgeranyltransferase activity - term: id: GO:0046474 label: glycerophospholipid biosynthetic process evidence_type: IEA original_reference_id: GO_REF:0000104 qualifier: involved_in supporting_entities: - UniRule:UR000076516 review: action: ACCEPT summary: Ether formation directly synthesizes an O-alkyl glycerophosphate lipid. reason: GO:0046474 includes glycerophosphate derivatives bearing at least one O-alkyl group. The characterized GGGPS reaction directly forms that ether-linked product and therefore performs the biosynthetic step. Native downstream processing and the physiological role of the C20 product remain unresolved. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: PMID:24684232 supporting_text: family enzymes catalyse the formation of an ether bond between glycerol-1-phosphate and polyprenyl diphosphates reference_section_type: ABSTRACT - term: id: GO:0047294 label: phosphoglycerol geranylgeranyltransferase activity evidence_type: EXP original_reference_id: PMID:24684232 qualifier: enables review: action: ACCEPT summary: The specific ether-forming prenyltransferase reaction is supported. reason: PMID:24684232 characterizes bacterial group II GGGPS, including fjGGGPS, and the curated target FUNCTION statement specifies the C20 GGPP/G1P reaction. Figure 5 distinguishes engineered I90A acceptance of HepPP from wild type; that mutant capacity does not establish native C35 synthesis. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/PMID24684232-fulltext-scope.md supporting_text: The I90A mutant clearly accepted HepPP as substrate, in contrast to the wild-type enzyme - term: id: GO:0047294 label: phosphoglycerol geranylgeranyltransferase activity evidence_type: IEA original_reference_id: GO_REF:0000120 qualifier: enables supporting_entities: - ARBA:ARBA00098378 - InterPro:IPR010946 - RHEA:23404 - EC:2.5.1.41 - UniRule:UR000076516 review: action: ACCEPT summary: The specific ether-forming prenyltransferase reaction is supported. reason: The electronic substrate-specific claim agrees with the target experimental row and curated FUNCTION statement linked to PMID:24684232. Acceptance rests on this independent characterization, not on ARBA alone. The engineered I90A HepPP result does not extend wild-type specificity to C35. supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/PMID24684232-fulltext-scope.md supporting_text: The I90A mutant clearly accepted HepPP as substrate, in contrast to the wild-type enzyme references: - id: GO_REF:0000002 title: Gene Ontology annotation through association of InterPro records with GO terms findings: [] - id: GO_REF:0000104 title: Electronic Gene Ontology annotations created by transferring manual GO annotations between related proteins based on shared sequence features findings: [] - id: GO_REF:0000118 title: TreeGrafter-generated GO annotations findings: [] - id: GO_REF:0000120 title: Combined Automated Annotation using Multiple IEA Methods findings: [] - id: PMID:24684232 title: A comprehensive analysis of the geranylgeranylglyceryl phosphate synthase enzyme family identifies novel members and reveals mechanisms of substrate specificity and quaternary structure organization. findings: - statement: Bacterial group II GGGPS enzymes are distinguished from group I HepGP synthases; target-specific experimental detail is in the reviewed record. supporting_text: the previously uncharacterized bacterial enzymes from group II have GGGPS activity like the archaeal enzymes and differ from the bacterial group I enzymes that are heptaprenylglyceryl phosphate synthases. reference_review: relevance: HIGH correctness: VERIFIED review_notes: Full publisher text independently read on 2026-11-07; frozen local cache remains abstract-only. Figure2 assays comparative donor capacity in a B.subtilis delta-pcrB host, not native donor-species downstream pathways. Figure5 distinguishes fjGGGPS I90A from wild type; groupII Mg is modeled, not observed density. - id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt title: Frozen reviewed UniProtKB A5FJK8 record findings: - statement: Record establishes strain, locus, curated mechanistic family and target-specific structural linkage. reference_review: relevance: HIGH correctness: VERIFIED review_notes: Experimental ECO0000269 statements distinguished from curated HAMAP inference. Gene labels, GO lines and ARBA text are not used as functional evidence. - id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/identity-and-scope.md title: Comparative-member structural identity and reaction-scope audit findings: - statement: Official PDBe mappings separate the two bacterial PcrBs, bacterial C20 GGGPS, and archaeal structural comparator. - id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/PMID24684232-fulltext-scope.md title: Primary full-text assay-host, mutant and structural scope check findings: - statement: Host-dependent donor tests and engineered mutant specificity must not be treated as native pathway completeness or wild-type C35 capability. core_functions: - description: C20 geranylgeranyl transfer to sn-glycerol-1-phosphate; native product function remains unresolved and mutant HepPP acceptance is not wild-type C35 capability. molecular_function: id: GO:0047294 label: phosphoglycerol geranylgeranyltransferase activity directly_involved_in: - id: GO:0046474 label: glycerophospholipid biosynthetic process supported_by: - reference_id: file:FLAJ1/Fjoh_1584/Fjoh_1584-uniprot.txt record_section: - CC:FUNCTION supporting_text: Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). - reference_id: file:analysis/module_audits/bacterial_heptaprenylglyceryl_ether_lipid/comparative-members/PMID24684232-fulltext-scope.md supporting_text: The I90A mutant clearly accepted HepPP as substrate, in contrast to the wild-type enzyme knowledge_gaps: - gap_statement: The physiological function and downstream fate of the native C20 ether product in F. johnsoniae are unresolved. gap_kind: - BIOLOGY dark_aspect: BP_DARK boundary: The C20 ether-forming reaction is established in biochemical assays. Its native cellular role, product abundance, and downstream transformations in F. johnsoniae UW101 remain unresolved. resolution: Identify native lipid products and perturb downstream candidate genes, coupling lipidomics to rescue and envelope phenotypes. status: OPEN suggested_questions: - question: What is the native role of the C20 GGGP product, and which enzymes use it in UW101?