ArnE/ArnF lipid A L-Ara4N donor flipping

A focused inner-membrane submodule of polymyxin-resistance lipid A modification in which ArnF acts with ArnE to move undecaprenyl-phosphate-alpha-L-Ara4N from the cytoplasmic leaflet to the periplasmic leaflet, positioning the lipid-linked aminoarabinose donor for ArnT-dependent transfer to lipid A. BasS/BasR-PmrA/PmrB induction, upstream ArnBCAD synthesis of the donor, and the ArnT transfer reaction are outside this reviewed ArnF-anchored module.

MODULE:lipid_a_l_arabinose_modificationDRAFTCONCRETETransport Stepmodules/lipid_a_l_arabinose_modification.yaml
intramembrane lipid transporter activityGO:0140303 lipopolysaccharide biosynthetic processGO:0009103
GO:0140303
intramembrane lipid transporter activity
Defines the intramembrane lipid-flipping activity of ArnE/ArnF.
GO:0009103
lipopolysaccharide biosynthetic process
Defines the lipopolysaccharide pathway that receives the ArnE/ArnF-flipped L-Ara4N donor.
file:genes/ECOLI/arnF/arnF-ai-review.yaml
ECOLI arnF gene review
The completed E. coli arnF review grounds ArnF as a subunit of the undecaprenyl-phosphate-alpha-L-Ara4N flippase.
file:genes/ECOLI/arnE/arnE-ai-review.yaml
ECOLI arnE gene review
The completed E. coli arnE review grounds ArnE as the partner subunit of the undecaprenyl-phosphate-alpha-L-Ara4N flippase.
PMID:17928292
An undecaprenyl phosphate-aminoarabinose flippase required for polymyxin resistance in Escherichia coli.
Establishes that ArnE/PmrL and ArnF/PmrM are required for periplasmic accessibility of undecaprenyl-phosphate-alpha-L-Ara4N, L-Ara4N-modified lipid A, and polymyxin resistance.

The completed ArnE and ArnF ECOLI reviews both support the focused flippase module. GO lacks an exact substrate-specific intramembrane lipid flippase child of GO:0140303, so the module uses the parent GO molecular-function term and records the ontology gap.

1Nodes
0Parts
0Variant Sets
0Variants
1Annotons
0Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:lipid_a_l_arabinose_modification deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

0 gene-function check(s) reflected in core functions · 0 conflict(s) · 0 evidence or coverage gap(s) (1 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
arne_arnf_l_ara4n_flippase PROTEIN_COMPLEX
Gene 		undecaprenyl-phosphate-L-Ara4N flippase activity
GO:0140303 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.

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

2 complete review(s) · 1 with deep research · 0 missing review · 1 reviewed but lacking deep research

Gene Review Complete Deep research
arnE Q47377 ✓ ✓ ✗
arnF P76474 ✓ ✓ ✓

Details

Context
bacteriaNCBITaxon:2
ArnE/ArnF lipid A L-Ara4N donor flippingTransport Steplipid_a_l_arabinose_modification
intramembrane lipid transporter activityGO:0140303 lipopolysaccharide biosynthetic processGO:0009103
Context
bacteriaNCBITaxon:2

Annotons

ArnE/ArnF L-Ara4N flippase
arne_arnf_l_ara4n_flippase
Participant: Protein Complex: E. coli ArnE/ArnF L-Ara4N flippase
Protein Complex:
E. coli ArnE/ArnF L-Ara4N flippase
Active units:
ArnE flippase subunit
Participant: Gene Product: E. coli ArnE
Gene Product:
E. coli ArnEUniProtKB:Q47377
Role: Inner-membrane subunit required for L-Ara4N donor flipping.
ArnF flippase subunit
Participant: Gene Product: E. coli ArnF
Gene Product:
E. coli ArnFUniProtKB:P76474
Role: Inner-membrane subunit required for L-Ara4N donor flipping.

Function

undecaprenyl-phosphate-L-Ara4N flippase activityGO:0140303
Substrates: cytoplasmic-leaflet undecaprenyl-phosphate-alpha-L-Ara4N
Products: periplasmic-leaflet undecaprenyl-phosphate-alpha-L-Ara4N

Processes

lipid A metabolic processGO:0046493 lipopolysaccharide biosynthetic processGO:0009103 carbohydrate derivative transportGO:1901264

Locations

plasma membraneGO:0005886

ArnE and ArnF form an inner-membrane flippase that moves the lipid-linked L-Ara4N donor across the inner membrane before ArnT modifies lipid A.