VIRION
Non-enveloped, head-tail structure. The icosahedral head is about 66 nm in diameter. The non-contractile tail is about 220-230 nm in length and 13 nm in width with about 55 cross-striations. There is an extremely long tail fiber measuring approximately 200-220 nm in length.
GENOME
Linear dsDNA genome of 59 kb, containing about 75 genes. The genome has cohesive ends.
GENE EXPRESSION
ENZYMES
- DNA polymerase I [A0A097P464]
- DNA primase [M9NUS5]
- Protease (Peptidase S49) [A0A097P489]
- Terminase [M9NUS7]
- Phosphoadenosine phosphosulphate reductase [M9NUR8]
REPLICATION
CYTOPLASMIC
- Adsorption: The phage attaches to target cell adhesion receptors through its tail fibers. Bacteriophage chi attaches to the filament of a bacterial flagellum, but the entry receptor site is located at the base of the bacterial flagellum.
- Ejection of the viral DNA into host cell cytoplasm by long flexible tail ejection system.
- Transcription and translation of early genes.
- Replication of genomic DNA.
- Transcription and translation of late genes
- Assembly of an empty procapsid and packaging of the genome.
- Viral tail fiber assembly and viral tail assembly.
- Mature virions are released from the cell by lysis.