A2FPI7

UniProt ID: A2FPI7
Organism: Trichomonas vaginalis (strain ATCC PRA-98 / G3)
Review Status: DRAFT
Aliases:
TVAG_233530 TVAG_559790
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Gene Description

A2FPI7 (TVAG_233530/TVAG_559790) is a 129-amino-acid KilA-N domain-containing protein from Trichomonas vaginalis. The KilA-N domain (Pfam PF04383) was originally identified in bacteriophage proteins associated with DNA-binding and transcriptional regulatory functions, and is structurally related to the APSES DNA-binding domain found in fungal transcription factors. T. vaginalis harbors numerous laterally transferred genes of viral and bacterial origin in its unusually large genome (~160 Mb). Based on conserved domain architecture, A2FPI7 is most likely a DNA-binding protein with a possible role in transcriptional regulation. No direct experimental characterization of this protein has been reported; the protein existence level is PE4 (Predicted), and no GO annotations are present in GOA.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0003677 DNA binding
ISM
file:TRIV3/A2FPI7/A2FPI7-deep-research-falcon.md 		NEW
Summary: DNA binding is inferred from the KilA-N domain (PF04383/IPR017880), which belongs to the KilA-N/APSES helix-turn-helix superfamily. This domain has been experimentally validated as a DNA-binding domain in fungal APSES transcription factors and bacteriophage regulatory proteins. ProtNLM2 also independently predicted this term. No direct experimental evidence exists for A2FPI7.
Reason: Domain-based inference strongly supports DNA binding as the primary molecular function; independently predicted by ProtNLM2.
Supporting Evidence:
file:TRIV3/A2FPI7/A2FPI7-deep-research-falcon.md
the strongest evidence-based inference is therefore that its primary molecular role is likely DNA binding, with possible participation in gene-expression control
GO:0005634 nucleus
ISM
file:TRIV3/A2FPI7/A2FPI7-deep-research-falcon.md 		NEW
Summary: Nuclear localization is inferred from the predicted DNA-binding function. DNA-binding transcriptional regulators characteristically function in the nucleus. However, T. vaginalis has an atypical nuclear architecture and this localization has not been experimentally verified for A2FPI7.
Reason: Inferred localization based on predicted DNA-binding function; awaits experimental confirmation.
Supporting Evidence:
file:TRIV3/A2FPI7/A2FPI7-deep-research-falcon.md
The most likely cellular localization for a DNA-binding regulatory protein is the nucleus, but this remains an inference from domain architecture

Core Functions

A2FPI7 is predicted to bind DNA based on the presence of a KilA-N domain (PF04383), which belongs to the KilA-N/APSES helix-turn-helix superfamily. This domain has been experimentally demonstrated to mediate sequence-specific DNA binding in fungal APSES transcription factors and in bacteriophage regulatory proteins. No direct experimental evidence exists for A2FPI7 specifically; this annotation is a domain-based inference.

Molecular Function:
DNA binding
Cellular Locations:
nucleus
Supporting Evidence:
  • file:TRIV3/A2FPI7/A2FPI7-deep-research-falcon.md
    the strongest evidence-based inference is therefore that its primary molecular role is likely DNA binding, with possible participation in gene-expression control
  • file:TRIV3/A2FPI7/A2FPI7-uniprot.txt
    RecName: Full=KilA-N domain-containing protein {ECO:0000259|PROSITE:PS51301}

References

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Suggested Questions for Experts

Q: Is A2FPI7 (TVAG_233530) expressed at the protein level in T. vaginalis, and if so, does it localize to the nucleus? T. vaginalis has an atypical nuclear architecture, and confirming nuclear localization would strengthen the transcription factor hypothesis.

Q: Does A2FPI7 bind DNA in vitro (e.g., via EMSA or ChIP-seq), and if so, does it show sequence-specific binding similar to fungal APSES domain proteins?

Q: Is the TVAG_233530 locus part of a laterally transferred genomic island of viral origin, and are there paralogous KilA-N domain proteins in the T. vaginalis genome with overlapping or distinct functions?

Suggested Experiments

Experiment: Express recombinant A2FPI7 and perform electrophoretic mobility shift assay (EMSA) with random and designed DNA probes to test for DNA-binding activity. Include a KilA-N domain deletion mutant as a negative control.

Hypothesis: A2FPI7 binds double-stranded DNA via its KilA-N domain.

Type: EMSA

Experiment: Tag A2FPI7 with GFP or an epitope tag, express it in T. vaginalis, and determine subcellular localization by fluorescence microscopy with DAPI co-staining for nuclear DNA.

Hypothesis: A2FPI7 localizes to the T. vaginalis nucleus.

Type: fluorescence microscopy

External Prediction Reviews

These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.

ProtNLM2 External predictions

View prediction review YAML · A2FPI7-protnlm-predictions-review.yaml · Review status: COMPLETE

The nearly complete KilA-N DNA-binding domain supports a broad DNA-binding inference without specifying a regulatory target.

Source documents: genes/TRIV3/A2FPI7/A2FPI7-uniprot.txt · genes/TRIV3/A2FPI7/A2FPI7-goa.tsv · publications/PMID_11897024.md

Review score: 2 = concordant with evidence; 1 = uncertain; 0 = discordant with evidence. This is an assessment score, not a model probability.

GO:0003677 DNA binding GO_MF
COR — Correct novel prediction Review score: 2/2
Prediction method: ProtNLM2 · Version: UniProt 2024_06 pilot
Review rationale: The 129-residue target contains a KilA-N domain spanning residues 19–124 and a KilA/APSES helix-turn-helix assignment. The primary comparative analysis defining KilA-N identifies a conserved DNA-binding module in viral and cellular regulatory proteins (PMID:11897024). This provides a domain-based inference for broad DNA binding, not an experimental binding measurement on Trichomonas A2FPI7 or evidence for a specific DNA sequence. The molecular function is absent from the cached annotations.
Supporting Evidence:
  • file:TRIV3/A2FPI7/A2FPI7-uniprot.txt: "ID A2FPI7_TRIV3 Unreviewed; 129 AA. ... DR InterPro; IPR018004; KilA/APSES_HTH. ... DR InterPro; IPR017880; KilA_N. ... FT DOMAIN 19..124 ... FT /note="KilA-N""
  • PMID:11897024: "a novel, conserved DNA-binding domain (the KilA-N domain)"

Deep Research

Falcon

(A2FPI7-deep-research-falcon.md)

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