Non-enveloped, head-tail structure. The icosahedral head is about 85 nm in diameter and virions also produce head size variants (about 47-65 nm). The tail is long, 228 x 18 nm, contractile, has six 90 nm-long kinked fibers and a base plate.


Linear, dsDNA genome of about 100 kb, encoding for approximately 100 proteins. The genome is terminally redundant and circularly permuted.


Genes are transcribed by operons.



  1. Adsorption: the phage attaches to the target cell through its tail fibers. Two types of fibers are encoded by the phage to allow receptor tropism switching.
  2. Ejection of the viral DNA into host cell cytoplasm by contraction of the tail sheath.
  3. Transcription and translation of early genes.
  4. Synthesis of linear concatemers copies of viral DNA. Transcription and translation of late genes.
  5. Assembly of an empty procapsid and packaging of the genome.
  6. Viral tail fibers assembly and viral tail assembly.
  7. Mature virions are released from the cell by lysis.

Matching UniProtKB/Swiss-Prot entries

30 entries grouped by strain (browse by keywords)

26 entries

Escherichia phage P1 (Bacteriophage P1) reference strain

REPL_BPP1 Replication protein repL
SSB_BPP1 Single-stranded DNA-binding protein (SSB-P1)
TERL_BPP1 Probable terminase, large subunit (EC 3.1.-.-) (DNA-packaging protein B) (PACase B protein) ...
REF_BPP1 Recombination enhancement function protein
U2_BPP1 Tail fiber assembly protein U' (Gene product U') (gpU')
PHD_BPP1 Antitoxin phd (Addiction protein pdh) (Prevent host death protein)
T3RE_BPP1 Type III restriction-modification system EcoPI enzyme res (EC
ENLYS_BPP1 SAR-endolysin (EC (Endolysin) (Gene product 17) (gp17) (Lysis protein) (Lysozyme) ...
DMT_BPP1 Methyltransferase Dmt (EC 2.1.1.-)
DARA_BPP1 Defense against restriction protein A (DarA)
CIN_BPP1 DNA-invertase (Site-specific recombinase)
KILA_BPP1 Protein kilA
DARB_BPP1 Defense against restriction protein B (EC 3.6.4.-) (DarB)
DOC_BPP1 Protein kinase doc (EC (Death on curing protein) (Toxin doc)
BOF_BPP1 Modulator protein
LPA_BPP1 Late promoter-activating protein (Gp10)
U1_BPP1 Tail fiber assembly protein U (Gene product U) (gpU)
VGR_BPP1 Tail fiber protein R (GpR)
RPC4_BPP1 Repressor protein C4
T3MO_BPP1 Type III restriction-modification system EcoPI enzyme mod (M.EcoPI) (EC (EcoPI ...
YORA_BPP1 Uncharacterized 36.0 kDa protein in doc-Gp10 intergenic region (ORFA)
PACA_BPP1 Terminase A protein (DNA-packaging protein A) (PACase A protein)
RPC1_BPP1 Repressor protein C1
ANT_BPP1 Antirepressor protein 1 (ant1) (Repressor bypass protein B) (rebB) [Cleaved into: Antirepressor ...
TEC_BPP1 Protein tec

4 entries

Enterobacteria phage P7 (Bacteriophage P7)

RPC1_BPP7 Repressor protein C1 (P7c1)
TERL_BPP7 Probable terminase, large subunit (EC 3.1.-.-) (DNA-packaging protein B) (PACase B protein) ...
PACA_BPP7 Terminase A protein (DNA-packaging protein A) (PACase A protein)
CIN_BPP7 DNA-invertase (Site-specific recombinase)