DNA polymerase I from Yersinia phage phiR8-01 (g022). This is a phage-encoded DNA-directed DNA polymerase (EC 2.7.7.7) that catalyzes the synthesis of DNA during viral genome replication. The protein belongs to DNA polymerase family A and contains a characteristic palm domain for nucleotidyltransferase activity.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003677 DNA binding | IEA GO_REF:0000002 | REMOVE | Summary: While DNA polymerases do bind DNA, this term is too general and does not capture the specific catalytic function. The more specific term DNA-directed DNA polymerase activity (GO:0003887) already implies DNA binding and better represents the molecular function. Reason: Correctly identified as overly general. DNA binding is inherent in DNA polymerase activity and adds no additional functional information. The specific molecular function GO:0003887 is more informative. Supporting Evidence: PMID:35357498 The conserved DNA polymerase PolA motifs A, B and C could be identified from the sequences of several of the most closely related proteins (Supplementary Figures S8 and S9) further confirming the possibility that DNAP01 is a functional DNA polymerase |
| GO:0003887 DNA-directed DNA polymerase activity | IEA GO_REF:0000120 | ACCEPT | Summary: This is the core molecular function of the protein, directly supported by the EC number 2.7.7.7 and UniProt annotation as "DNA polymerase I, phage-associated". The InterPro domains confirm DNA polymerase family A membership. Reason: Correctly identified as the core function. EC 2.7.7.7 directly corresponds to DNA-directed DNA polymerase activity. UniProt domain annotation (residues 483-738) and InterPro family classification strongly support this annotation. Supporting Evidence: PMID:35357498 DNAP01 was indeed able to replicate the YerA41 DNA thereby creating a non-modified DNA-product... Furthermore, the DNAP01 polymerase did not require any added specific or random hexamer primers for its activity with the YerA41 genomic material |
| GO:0006259 DNA metabolic process | IEA GO_REF:0000117 | TOO GENERAL | Summary: This term is too broad and non-specific. The more specific terms "DNA-templated DNA replication" (GO:0006261) and "viral DNA genome replication" (GO:0039693) better describe the biological process. Reason: DNA metabolic process is true of g022 but uninformative: DNA replication (GO:0006260) and DNA-templated DNA replication (GO:0006261), kept as non-core, and viral DNA genome replication (GO:0039693), ACCEPTed, all entail it. Retired because absent from GOA as of the 2026-07-27 QuickGO release (GOA refresh 2026-09-29); the review is kept for provenance. |
| GO:0006260 DNA replication | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Accurate but somewhat general. The more specific term "viral DNA genome replication" (GO:0039693) is more appropriate for a phage polymerase, making this term redundant. Reason: Upon further consideration, this annotation should be kept as non-core rather than removed. While viral DNA genome replication is more specific, DNA replication is still accurate and represents the broader biological process. This follows GO annotation principles where both general and specific terms can coexist. Supporting Evidence: PMID:35357498 DNAP01 was indeed able to replicate the YerA41 DNA thereby creating a non-modified DNA-product |
| GO:0006261 DNA-templated DNA replication | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: Appropriate biological process for a DNA polymerase. However, the more specific term "viral DNA genome replication" (GO:0039693) better captures the viral context, making this general term less necessary. Reason: Correctly identified as non-core. This term accurately describes the mechanism (DNA-templated) but lacks the viral specificity that is the key characteristic of this polymerase. Both general and specific terms are valuable in GO annotation. Supporting Evidence: PMID:35357498 When host polymerases are unable to replicate the viral genome, the bacteriophage produces its own polymerase that can function using the modified DNA as a template |
| GO:0006302 double-strand break repair | IEA GO_REF:0000118 | REMOVE | Summary: TreeGrafter prediction likely based on homology to bacterial DNA polymerase I which has repair functions. However, phage DNA polymerases are primarily dedicated to viral genome replication, not host DNA repair. No evidence supports this specific repair function in the phage context. Reason: This annotation should be removed rather than marked as over-annotated. There is no evidence that this phage polymerase functions in double-strand break repair. The TreeGrafter prediction appears to be based on superficial homology to bacterial Pol I without considering the specialized viral context. Phage polymerases are optimized for rapid viral genome replication, not DNA repair processes. Retired because absent from GOA as of the 2026-07-27 QuickGO release (GOA refresh 2026-09-29); the review is kept for provenance. Supporting Evidence: PMID:35357498 Unlike commercially available DNA polymerases, the DNA polymerase coded by the phage's genome should be able to amplify its own modified DNA |
| GO:0016740 transferase activity | IEA GO_REF:0000043 | TOO GENERAL | Summary: Too general. DNA polymerases are transferases, but the specific term "DNA-directed DNA polymerase activity" (GO:0003887) already encompasses this and is more informative. Reason: Correctly identified as overly general. Transferase activity is a very broad enzyme classification that includes many different types of enzymes. The specific DNA polymerase molecular function term provides much more biological information. TOO_GENERAL rather than REMOVE: DNA-directed DNA polymerase activity, kept in this review, entails this term, so the claim is true but less informative. |
| GO:0016779 nucleotidyltransferase activity | IEA GO_REF:0000043 | TOO GENERAL | Summary: While accurate (DNA polymerases are nucleotidyltransferases), this is less specific than "DNA-directed DNA polymerase activity" (GO:0003887) which better describes the molecular function. Reason: Correctly identified as less informative than the specific polymerase term. While technically accurate, nucleotidyltransferase activity encompasses many different enzymes including various polymerases, kinases, and other transferases. The DNA polymerase-specific annotation is more valuable. Retired because absent from GOA as of the 2026-07-27 QuickGO release (GOA refresh 2026-09-29); the review is kept for provenance. TOO_GENERAL rather than REMOVE: DNA-directed DNA polymerase activity, kept in this review, entails this term, so the claim is true but less informative. |
| GO:0039693 viral DNA genome replication | IEA GO_REF:0000043 | ACCEPT | Summary: Highly appropriate and specific biological process for a phage DNA polymerase. This accurately describes the primary role of this protein in viral replication. Reason: Correctly identified as the most appropriate biological process annotation. This term specifically captures the viral context and primary function of this phage-encoded polymerase. This is the core biological process that the enzyme performs. Supporting Evidence: PMID:35357498 The presence of DNAP01 in the phage particles (8) implicates that it is delivered along with the genomic material from the phage particles upon infection into the host bacteria |
| GO:0016779 nucleotidyltransferase activity | IEA GO_REF:0000120 | TOO GENERAL | Summary: Accurate but uninformative parent of DNA-directed DNA polymerase activity (GO:0003887), which is already annotated. Same term as the retired GO_REF:0000043 keyword row, now delivered through the GO_REF:0000120 merge (ARBA + KW-0548). Reason: Redundant with the accepted, more specific GO:0003887. Kept consistent with the earlier review of the keyword-derived row for the same term. TOO_GENERAL rather than REMOVE: DNA-directed DNA polymerase activity, kept in this review, entails this term, so the claim is true but less informative. |
| GO:0071897 DNA biosynthetic process | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: Correct but general. A DNA polymerase performs DNA synthesis, so the protein does carry out part of DNA biosynthesis; the informative process is viral DNA genome replication (GO:0039693), which is already accepted. Reason: True for any replicative DNA polymerase and consistent with the non-core treatment of DNA replication (GO:0006260) in this review; the viral replication term carries the biological context. |
| GO:0140640 catalytic activity, acting on a nucleic acid | IEA GO_REF:0000117 | TOO GENERAL | Summary: High-level grouping term (catalytic activity, acting on a nucleic acid) that is a distant ancestor of the accepted DNA-directed DNA polymerase activity (GO:0003887). Reason: Adds no information beyond GO:0003887; treated the same way as the other generic MF rows here (transferase activity, nucleotidyltransferase activity). TOO_GENERAL rather than REMOVE: DNA-directed DNA polymerase activity, kept in this review, entails this term, so the claim is true but less informative. |
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Download this section (compressed HTML)Q: Does g022 have 3'-5' exonuclease (proofreading) activity? A NEW GO:0008296 proposal was withdrawn because the only support was family A membership, which does not imply proofreading. The UniProt record shows only the family A palm domain (483-738) and a Gene3D 1.10.150.20 5'-3' exonuclease C-terminal subdomain, with no 3'-5' exonuclease (DnaQ-like/DEDDy) domain signature, at 815 aa. PANTHER subfamily PTHR10133:SF27 is uninformative here, because it mixes proofreading-proficient members (E. coli Pol I, T7 gene 5) with proofreading-deficient ones despite its "DNA polymerase nu" name.
Experiment: Align the N-terminal region of g022 against proofreading family A polymerases (E. coli Pol I Klenow, T7 gene 5) to test for the Exo I-III DEDD motif carboxylates. Then assay purified g022 for 3'-terminal mismatch excision on a primer-template, with an exonuclease-dead mutant as a control.
Hypothesis: g022 lacks intrinsic 3'-5' exonuclease activity.
Type: enzyme assay
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Download this section (compressed HTML)📊 View Pathway Visualization Interactive pathway diagram with detailed annotations