Non-enveloped, round, T=1 icosahedral symmetry, about 30 nm in diameter. The capsid consists of 12 pentagonal trumpet-shaped pentomers. The virion is composed of 60 copies each of the F, G, and J proteins, and 12 copies of the H protein. There are 12 spikes which are each composed of 5 G and one H proteins.


Circular, ssDNA(+) genome of 4.4 to 6.1kb. replication occurs via dsDNA intermediate and rolling circle.


Early and late genes promoters tightly regulate the timing of gene expression, which is crucial for the replication cycle.



  1. Pilus-mediated adsorption of the virus onto host cell
  2. The proteins of the capsid perform Injection of the viral DNA through bacterial membranes into cell cytoplasm.
  3. Host polymerase convert the (+)ssDNA viral genome into a covalently closed dsDNA called replicative form DNA I (RF-I).
  4. Early viral genes are transcribed by host RNA polymerase, producing viral replication proteins.
  5. Viral protein A cleaves RF-I(+) DNA strand at the origin of replication and covalently attaches itself to the DNA.
  6. (+)strand replication occurs by rolling circle, which is converted to dsDNA by host polymerase, generating RF-II molecules (amplification of RF-I).
  7. Late viral genes are transcribed by host RNA polymerase.
  8. Procapsid assembly in the cytoplasm.
  9. Viral protein C binds to replication complex, inducing synthesis and packaging of neo-synthesized (+)ssDNA genomes (RF-III) into procapsids.
  10. Procapsids maturation occurs in host cytoplasm
  11. Mature virions are released from the cell by lysis.

Matching UniProtKB/Swiss-Prot entries

20 entries grouped by strain (browse by keywords)

10 entries

Enterobacteria phage G4 (Bacteriophage G4) reference strain

Select_all Deselect_all  
G_BPG4Major spike protein G (G protein) (GPG)
SCAFB_BPG4Internal scaffolding protein B (Scaffolding protein B) (GPB)
SCAFD_BPG4External scaffolding protein D (Scaffolding protein D) (GPD)
VGA_BPG4A protein (GPA)
VGC_BPG4C protein
VGE_BPG4Lysis protein (E protein) (GPE)
VGF_BPG4Capsid protein (F protein) (GPF)
VGH_BPG4Minor spike protein (H protein) (Pilot protein)
VGJ_BPG4Small core protein (J protein)
VGK_BPG4K protein

10 entries

Enterobacteria phage phiK (Bacteriophage phi-K)

Select_all Deselect_all  
G_BPPHKMajor spike protein G (G protein) (GPG)
SCAFB_BPPHKInternal scaffolding protein B (Scaffolding protein B) (GPB)
SCAFD_BPPHKExternal scaffolding protein D (Scaffolding protein D) (GPD)
VGA_BPPHKA protein (GPA)
VGC_BPPHKC protein
VGE_BPPHKLysis protein (E protein) (GPE)
VGF_BPPHKCapsid protein (F protein) (GPF)
VGH_BPPHKMinor spike protein (H protein) (Pilot protein)
VGJ_BPPHKSmall core protein (J protein)
VGK_BPPHKK protein