Non-enveloped, head-tail structure. Heads are about 84-94 nm in diameter and and tails 140-219 in length. The tail is contractile with globular structures at its tip, has 6 long terminal fibers, 6 short spikes and a double base plate. The capsid has a T=16 symmetry (SPO1-like viruses).


Linear, dsDNA genome of 130-140 kb, encoding for about 190-215 proteins.


Genes are transcribed by operons. Some Twortvirus might have circularly permuted genomes.



  1. Adsorption: the phage attaches to the target cell through its tail fibers.
  2. Ejection of the viral DNA into host cell cytoplasm by contraction of the tail sheath.
  3. Transcription and translation of early genes.
  4. Replication of genomic 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

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57 entries grouped by strain

5 entries

Bacillus phage SP01 (Bacteriophage SP01) reference strain

GP46_BPSP1 Inhibitor of histone-like protein HU (Gene 46 protein) (Gp46) (Gene product 46)
GP56_BPSP1 Inhibitor of host cell division protein (Gene 56 protein) (Gp56)
DUHM_BPSP1 Deoxyuridylate hydroxymethyltransferase (Deoxyuridylate hydroxymethylase) (EC 2.1.2.-) (Gp29) (dUMP ...
PORTL_BPSP1 Probable portal protein
TSP_BPSP1 Tail sheath protein (TSP)

8 entries

Enterococcus phage phiEF24C (Enterococcus bacteriophage phi-EF24C) reference strain

PORTL_BPPHE Probable portal protein
VPN7_BPPHE Tail fiber protein
VPN1_BPPHE Putative tail sheath protein
VPN2_BPPHE Putative major capsid protein
BP40_BPPHE Virion protein 3 (Gene product 40) (gp40)
VPN4_BPPHE Virion protein 4
VPN5_BPPHE Virion protein 5
VPN6_BPPHE Virion protein 6

3 entries

Staphylococcus phage Twort (strain DSM 17442 / HER 48) (Bacteriophage Twort) reference strain

GP168_BPTWO Gene product 168 (gp168)
TSP_BPTWO Tail sheath protein (TSP)
PORTL_BPTWO Probable portal protein

1 entry

Bacillus phage BSP38 reference strain

APYC1_BPBSP Anti-Pycsar protein Apyc1 (Apyc1)

1 entry

Bacillus phage SP10 (Bacillus phage SP-10) reference strain

HMUDK_BPS10 5-hmdU DNA kinase (5-hydroxymethyluracil DNA kinase) (P-loop kinase) (gp186)

1 entry

Bacillus phage vB_BsuM-Goe3 reference strain

ACPY1_BPGO3 Anti-Pycsar protein Apyc1 (Apyc1)

1 entry

Bacillus phage vB_BveM-Goe7 reference strain

ACPY1_BPGO7 Anti-Pycsar protein Apyc1 (Apyc1)

1 entry

Staphylococcus phage K reference strain

CAPSD_BPPGK Major capsid protein (Major head protein)

31 entries

Bacillus phage SP01 (Bacteriophage SP01)

TF1_BPSP1 Transcription factor 1
DPOL_BPSP1 DNA polymerase (EC (EC 3.1.11.-)
RP28_BPSP1 RNA polymerase sigma GP28 factor
RP34_BPSP1 RNA polymerase sigma GP34 factor
GP27_BPSP1 Gene 27 protein
GP44_BPSP1 E3 protein (Gene 44 protein)
GP30_BPSP1 Gene 30 protein (GP30)
GP37_BPSP1 Putative gene 37 protein
GP38_BPSP1 Putative gene 38 protein
GP39_BPSP1 Putative gene 39 protein
GP40_BPSP1 Gene 40 protein
GP41_BPSP1 Putative gene 41 protein
GP42_BPSP1 Putative gene 42 protein
GP45_BPSP1 Putative gene 45 protein
GP47_BPSP1 Putative gene 47 protein
GP48_BPSP1 Putative gene 48 protein
GP49_BPSP1 Putative gene 49 protein
GP50_BPSP1 Putative gene 50 protein
GP51_BPSP1 Putative gene 51 protein
GP52_BPSP1 Putative gene 52 protein
GP53_BPSP1 Putative gene 53 protein
GP54_BPSP1 Putative gene 54 protein
GP55_BPSP1 Putative gene 55 protein
GP57_BPSP1 Putative gene 57 protein
GP58_BPSP1 Putative gene 58 protein
GP59_BPSP1 Putative gene 59 protein
GP60_BPSP1 Putative gene 60 protein
GP33_BPSP1 Gene 33 protein
YG29_BPSP1 Uncharacterized 16.2 kDa protein in gene 29 5'region
HMUI_BPSP1 DNA endonuclease I-HmuI (EC 3.1.-.-) (HNH homing endonuclease I-HmuI)
GP43_BPSP1 E22 protein (Gene 43 protein)

1 entry

Bacillus phage 010DV004

ACPY1_BP010 Anti-Pycsar protein Apyc1 (Apyc1)

1 entry

Bacillus phage SBSphiJ

APYC1_BPSBS Anti-Pycsar protein Apyc1 (Apyc1)

1 entry

Listeria phage A511 (Bacteriophage A511)

ENLYS_BPA51 Endolysin (EC (Probable N-acetylmuramoyl-L-alanine amidase)

1 entry

Staphylococcus phage S25-3

CAPSD_BPS25 Major capsid protein (Major head protein)

1 entry

Staphylococcus phage S25-4

CAPSD_BPS24 Major capsid protein (Major head protein)