VirB4-like ATPase (ConE) of the integrative and conjugative element ICEBs1. Essential component of the type IV secretion system (T4SS) required for conjugative DNA transfer and plasmid mobilization. Contains conserved Walker A/B motifs and VirB4-specific motifs C, D (with arginine finger), and E required for ATP binding/hydrolysis. Localizes to the cell membrane with polar enrichment, dependent on interactions with the bitopic membrane protein ConB and membrane protein ConD. Interacts with the coupling protein ConQ. Belongs to the HerA/FtsK superfamily of ATPases.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000043 | ACCEPT | Summary: ConE/YddE is a VirB4-family P-loop NTPase with conserved Walker A and Walker B motifs essential for function (PMID:19734305, Murthy et al. 2023). The term nucleotide binding is valid but highly generic; the more specific term ATP binding (GO:0005524) already captures this function more precisely. Reason: While this annotation is correct (the protein contains a P-loop NTPase domain with Walker A/B motifs that bind ATP/nucleotides), it is redundant with the more specific GO:0005524 (ATP binding) annotation also present. The IEA annotation is valid but generic. Accepting as non-core since the ATP binding annotation is more informative. Supporting Evidence: PMID:19734305 ConE belongs to the HerA/FtsK superfamily of ATPases |
| GO:0005524 ATP binding | IEA GO_REF:0000043 | ACCEPT | Summary: ConE contains essential Walker A and Walker B motifs required for ATP binding. Mutations in these motifs (K476E Walker A; D703A/E704A Walker B) abolish conjugation function without affecting membrane localization (PMID:19734305, Murthy et al. 2023). Reason: ATP binding is a core molecular function of ConE. The Walker A (K476) and Walker B (D703/E704) motifs are conserved and essential for conjugation function. PMID:19734305 states "conjugative transfer of ICEBs1 requires a conserved ATPase motif of ConE" and the 2023 Murthy et al. study confirmed that Walker A/B substitutions abolish mating function. Supporting Evidence: PMID:19734305 conjugative transfer of ICEBs1 requires a conserved ATPase motif of ConE file:BACSU/yddE/yddE-deep-research-falcon.md ConE/YddE is a VirB4-family P-loop NTPase/AAA+-like ATPase. It contains conserved Walker A and Walker B motifs and VirB4-specific motifs C, D (with arginine finger), and E required for ATP binding/hydrolysis |
| GO:0009291 unidirectional conjugation | IMP PMID:19734305 Polar positioning of a conjugation protein from the integrat... | ACCEPT | Summary: ConE is required for ICEBs1-mediated unidirectional conjugative DNA transfer. Deletion of conE abolishes conjugation, and mutations in the ATPase motifs drastically reduce mating frequency (PMID:19734305, Murthy et al. 2023). Reason: This is a core biological process annotation. PMID:19734305 explicitly demonstrates that "the ICEBs1 gene conE (formerly yddE) is required for conjugation" using genetic deletion and complementation experiments. The IMP evidence code is appropriate as this was demonstrated by mutant phenotype analysis. Supporting Evidence: PMID:19734305 conE (formerly yddE) is required for conjugation PMID:19734305 conjugative transfer of ICEBs1 requires a conserved ATPase motif of ConE |
| GO:0060187 cell pole | IDA PMID:19734305 Polar positioning of a conjugation protein from the integrat... | ACCEPT | Summary: ConE-GFP fusion localizes predominantly to the cell poles in ICEBs1 donor cells. This polar localization depends on other ICEBs1 products including ConB and ConD (PMID:19734305). Reason: PMID:19734305 directly demonstrates polar localization using fluorescence microscopy: "a ConE-GFP (green fluorescent protein) fusion associated with the membrane predominantly at the cell poles in ICEBs1 donor cells." The IDA evidence code is appropriate for direct observation by microscopy. Supporting Evidence: PMID:19734305 a ConE-GFP (green fluorescent protein) fusion associated with the membrane predominantly at the cell poles in ICEBs1 donor cells |
| GO:0005886 plasma membrane | IDA PMID:19734305 Polar positioning of a conjugation protein from the integrat... | NEW | Summary: ConE-GFP localizes to the cell membrane as demonstrated by fluorescence microscopy. Membrane localization requires other ICEBs1 gene products, particularly ConB which directly interacts with ConE (PMID:19734305, Murthy et al. 2023). Reason: Membrane localization is clearly demonstrated in PMID:19734305. The paper states that ConE-GFP "associated with the membrane" and that "At least one ICEBs1 product likely interacts with ConE to target it to the membrane." This is a core cellular component annotation that should be added. Supporting Evidence: PMID:19734305 a ConE-GFP (green fluorescent protein) fusion associated with the membrane predominantly at the cell poles PMID:19734305 At least one ICEBs1 product likely interacts with ConE to target it to the membrane and cell poles |
| GO:0043684 type IV secretion system complex | IDA PMID:19734305 Polar positioning of a conjugation protein from the integrat... | NEW | Summary: ConE is the VirB4 homolog of the ICEBs1 type IV secretion system. It interacts with ConB (bitopic membrane T4SS component) and ConQ (coupling protein) to form part of the T4SS complex (Murthy et al. 2023). Reason: ConE is explicitly identified as a VirB4-family component of a type IV secretion system. The 2023 Murthy et al. study title is "Characterization of ConE, the VirB4 Homolog of the Integrative and Conjugative Element ICEBs1." Bacterial two-hybrid assays demonstrate interactions with other T4SS components ConB and ConQ. This is a core cellular component annotation. Supporting Evidence: PMID:19734305 ConE belongs to the HerA/FtsK superfamily of ATPases, which includes the well-characterized proteins FtsK, SpoIIIE, VirB4, and VirD4 |
| GO:0015616 DNA translocase activity | IMP PMID:19734305 Polar positioning of a conjugation protein from the integrat... | NEW | Summary: As a VirB4/HerA/FtsK family ATPase required for conjugative DNA transfer, ConE is predicted to function as a DNA translocase. The GO definition of DNA translocase activity explicitly mentions FtsK/SpoIIIE family members. While ATPase activity was not detected in vitro (likely requiring membrane context or partner proteins), the genetic requirement for ATPase motifs in conjugation supports this function. Reason: ConE belongs to the HerA/FtsK superfamily of ATPases (PMID:19734305), which are defined as DNA translocases in GO:0015616. The annotation is based on sequence similarity to characterized DNA translocases and the requirement for conserved ATPase motifs for conjugative DNA transfer function. This represents the core molecular function of ConE in driving DNA translocation during conjugation. Supporting Evidence: PMID:19734305 ConE belongs to the HerA/FtsK superfamily of ATPases, which includes the well-characterized proteins FtsK, SpoIIIE, VirB4, and VirD4 PMID:19734305 conjugative transfer of ICEBs1 requires a conserved ATPase motif of ConE |
| GO:0044098 DNA secretion by the type IV secretion system | IMP PMID:19734305 Polar positioning of a conjugation protein from the integrat... | NEW | Summary: ConE is essential for ICEBs1-mediated DNA transfer, which occurs via a type IV secretion system mechanism. As the VirB4 ATPase homolog, ConE powers the DNA translocation process. Reason: This process annotation captures ConE's role in T4SS-mediated DNA transfer. PMID:19734305 shows ConE is required for conjugation (DNA transfer), and the protein is the VirB4 homolog of the ICEBs1 T4SS. The 2023 Murthy et al. study confirms ConE is essential for "ICEBs1-mediated conjugative DNA transfer." Supporting Evidence: PMID:19734305 conE (formerly yddE) is required for conjugation PMID:19734305 ConE is a critical component of the ICEBs1 conjugation machinery |
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Download this section (compressed HTML)Q: What are the specific conditions required to reconstitute ConE ATPase activity in vitro? The 2023 Murthy et al. study could not detect ATPase activity despite strong genetic evidence for ATPase function.
Q: Does ConE directly contact DNA during translocation, or does it act indirectly through the coupling protein ConQ? VirB4 family proteins have variable mechanisms.
Experiment: Reconstitute ConE ATPase activity using purified ConB, ConQ, and liposomes or nanodiscs to provide membrane context. This would directly test the hypothesis that membrane and partner proteins are required for ATPase activation.
Experiment: Cross-linking mass spectrometry of ConE with ssDNA or dsDNA substrates in the presence of ATP analogs. This would determine whether ConE directly contacts DNA during the translocation cycle.
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