VIRION
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Non-enveloped, head-tail structure. Head is about 90 nm nm in diameter. The tail is contractile of about 110x18nm, has star-like fibers. The tail consists of a neck with a collar, a sheath surrounding a tail tube or core, and a thin baseplate. The tail sheath has 24 transverse striations.
GENOME
Linear, dsDNA genome of about 157 kb, encoding for approximately 208 proteins.
GENE EXPRESSION
Genes are transcribed by operons.
ENZYMES
- DNA-directed DNA polymerase
- Cysteine protease (Peptidase C51)
- Endonuclease
- Topoisomerase
REPLICATION
CYTOPLASMIC
- 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.
- Ejection of the viral DNA into host cell cytoplasm by contraction of the tail sheath.
- Transcription and translation of early genes.
- Synthesis of linear concatemers copies of viral DNA. Transcription and translation of late genes.
- Assembly of an empty procapsid and packaging of the genome.
- Viral tail fibers assembly and viral tail assembly.
- Mature virions are released from the cell by lysis.