| Functional role/process | Molecular activity (substrate specificity/polarity) | Key interaction partners/modulators | Key quantitative/statistical findings | Evidence type (genetic/biochemical/structural/single-molecule) | Key citations (with year, journal, DOI URL) |
|---|---|---|---|---|---|
| Verified protein identity / core annotation | Bacteriophage T4 UvsW (Dar) is a ~55 kDa SF2 ATP-dependent helicase with canonical Walker A Lys141 and two RecA-like domains; branched-DNA specificity and 3′→5′ polarity are consistent with UniProt P0DXF1 | ATP; catalytic Lys141; structural similarity/function overlap with RecG and some biochemical similarity to RecQ | Walker A mutant K141R abolishes ATPase-dependent helicase functions; protein described as ~55 kDa | Structural, biochemical, genetic | Sickmier et al., 2004, *Structure*, https://doi.org/10.1016/j.str.2004.02.016; Carles-Kinch et al., 1997, *EMBO J.*, https://doi.org/10.1093/emboj/16.13.4142; Nelson & Benkovic, 2007, *J. Biol. Chem.*, https://doi.org/10.1074/jbc.m608153200 (pqac-00000005, pqac-00000006, pqac-00000013) |
| Regulation of T4 replication-mode switch | Unwinds RNA–DNA hybrids/R-loops at T4 origins, promoting the switch from origin-dependent to recombination-dependent (origin-independent) replication | Origin R-loops; ATP hydrolysis; late expression timing; RecG-like activity | Purified UvsW efficiently dissociates RNA from synthetic origin R-loops; UvsW expression increases recovery of *E. coli* rnhA::cat recG double mutants (example table entries 0.5 without UvsW vs 175 with UvsW in the cited excerpt) | Genetic and biochemical | Dudas & Kreuzer, 2001, *Mol. Cell. Biol.*, https://doi.org/10.1128/MCB.21.8.2706-2715.2001; Carles-Kinch et al., 1997, *EMBO J.*, https://doi.org/10.1093/emboj/16.13.4142 (pqac-00000007, pqac-00000008) |
| Branched-DNA helicase in recombination/repair | Unwinds a wide range of branched substrates, including stalled-fork mimics, D-loops, X- and Y-structures; 3′→5′ helicase/translocase | ATP; ATPγS inhibits annealing; gp32 can inhibit annealing and modulate helicase action; UvsW.1 forms a complex with UvsW | Strong polarity preference: 3′ overhang substrates are efficiently unwound/annealed relative to 5′ overhangs; example in vitro conditions in excerpt include 5 mM ATP, 2 nM DNA substrate, 200 nM protein at 37°C | Biochemical | Nelson & Benkovic, 2007, *J. Biol. Chem.*, https://doi.org/10.1074/jbc.m608153200; Perumal et al., 2013, *J. Mol. Biol.*, https://doi.org/10.1016/j.jmb.2013.05.012 (pqac-00000011, pqac-00000012, pqac-00000015) |
| Holliday junction branch migration | Drives ATP-dependent branch migration of Holliday junctions and acts on X-shaped replication intermediates | ATP required; K141R mutant binds/stabilizes HJs without productive ATP-driven migration; functionally linked with UvsX/UvsY pathways | Promotes branch migration efficiently through **>1000 bp** of DNA; ATPase-dead K141R fails to promote migration | Biochemical, 2D-gel, genetic | Webb et al., 2007, *J. Biol. Chem.*, https://doi.org/10.1074/jbc.m705913200 (pqac-00000010) |
| Active replication-fork regression / fork reversal | Catalyzes regression of origin-fork intermediates, converting forks into regressed Holliday-junction-like products by coupled unwinding/rewinding | ATP; Endonuclease VII (gene 49) implicated downstream in cleavage of regressed forks; K141R used as inactive control | In vivo, 46/uvsW infections are almost completely deficient for the **1.48-kb DSE fragment**; in vitro, increasing UvsW up to **250 nM** converts fork intermediates to **6.2- and 5.2-kb** products; example product fractions in excerpt rise to **94%** at highest enzyme condition | Genetic, biochemical, 2D-gel | Long & Kreuzer, 2009, *EMBO Rep.*, https://doi.org/10.1038/embor.2009.13 (pqac-00000014) |
| Stalled-fork restart and template switching | Couples fork regression with branch migration and fork restoration to enable lesion bypass and restart of T4 replication forks | T4 replisome/holoenzyme; ATP; reversible branch migration | Single-molecule assays measured annealing rates of about **1300 bp/s** at **15 pN**, processivity of about **9 kbp**, HJ migration rates about **1000–1300 bp/s**, characteristic direction-switching time about **2 s**; UvsW increased full replication past a leading-strand lesion by **>30-fold** and allowed bypass of a roadblock that otherwise arrested **98%** of molecules | Single-molecule | Manosas et al., 2012, *Science*, https://doi.org/10.1126/science.1225437 (pqac-00000031) |
| Robust DNA rewinding motor for fork rescue | Active rewinding enzyme that couples duplex rewinding to unwinding/protein displacement during fork regression; functional analog of RecG | ATP; fork junction ssDNA tails; parental duplex interaction over ~10 bp; divalent ions modulate branch-migration direction switching | Works against opposing loads up to **35 pN**; modeled step size **~1–2 bp**; fork-stabilization energy **~5–5.5 kBT**; maximum work per bp **~7.5 kBT**; estimated motor efficiency **~40–75%**; fork-binding on-rates **~5 × 10^6 M^-1 s^-1**; residence times roughly **15–20 s** in cited conditions | Single-molecule and modeling | Manosas et al., 2013, *Nat. Commun.*, https://doi.org/10.1038/ncomms3368 (pqac-00000032, pqac-00000033, pqac-00000034, pqac-00000036, pqac-00000037) |
| Strand annealing activity | Potent ssDNA annealing activity in addition to helicase function; annealing is enhanced by ATP hydrolysis but does not strictly require hydrolysis | gp32 inhibits annealing; ATPγS inhibits annealing; UvsW.1 inhibits/modulates annealing and forms complex with UvsW | Fusion with UvsW.1 yields a **68-kDa** protein with properties similar to the UvsW–UvsW.1 complex | Biochemical, FRET | Nelson & Benkovic, 2007, *J. Biol. Chem.*, https://doi.org/10.1074/jbc.m608153200 (pqac-00000013, pqac-00000015) |
| Functional interaction with T4 gp32 SSB | UvsW-catalyzed unwinding of recombination intermediates is enhanced by gp32, but gp32-coated ssDNA can suppress UvsW annealing/translocation unless the gp32 acidic tail mediates productive interaction | gp32 acidic C-terminal protein-interaction domain; ssDNA; ATP | Excerpt reports functional fluorescence assays using **500 nM** UvsW and gp32 variants; no direct affinity constant given in snippets | Biochemical | Perumal et al., 2013, *J. Mol. Biol.*, https://doi.org/10.1016/j.jmb.2013.05.012 (pqac-00000003, pqac-00000012) |
| Heterologous tool for bacterial R-loop biology | In *E. coli*, heterologous UvsW acts as an R-loop helicase and can reveal or relieve transcriptional blocks caused by pathological antisense R-loops | Rho deficiency context; bacterial antisense RNAs that form R-loops | 2024 study used UvsW expression to distinguish antisense loci detectable only under combined **Rho deficiency + UvsW**; these transcripts required UvsW unwinding to be synthesized in quantity and identified | Functional genomics / bacterial application | Pandiyan et al., 2024, *Nucleic Acids Res.*, https://doi.org/10.1093/nar/gkae839 (pqac-00000019, pqac-00000021) |
| Target/trigger in anti-phage defense | Phage-encoded UvsW is sensed by Retron-Eco11 as a defense trigger; retron activation depends on helicase catalytic activity rather than mere DNA binding | Retron-Eco11 msDNA, RT, PRTase-like effector; ATPase/helicase catalytic motifs; D10 is a functional analog trigger in T5 | Escape mapping placed **all five** T4 escape mutants in uvsW and **all five** T5 escape mutants in d10 in the cited excerpt; UvsW K141R fails to trigger toxicity; Retron-Eco11 activation linked to about **50% PRPP depletion** in later peer-reviewed follow-up | 2024 preprint genetics/heterologous expression; later peer-reviewed confirmation | García-Rodríguez et al., 2024, *bioRxiv*, https://doi.org/10.1101/2024.02.09.579579; García-Rodríguez et al., 2025, *Nucleic Acids Res.*, https://doi.org/10.1093/nar/gkaf1396 (pqac-00000024, pqac-00000027, pqac-00000028, pqac-00000029) |


*Table: This table summarizes the experimentally supported functional annotation of bacteriophage T4 UvsW/Dar, including its molecular activities, pathway roles, modulators, quantitative properties, and newer 2024 biological contexts. It is useful as a compact evidence map linking classical T4 replication/recombination studies with recent R-loop and anti-phage defense findings.*