Podoviridae

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Podoviridae
Virus classification
Group: Group I (dsDNA)
Order: Caudovirales
Family: Podoviridae
Sub-families

The Podoviridae are a family of bacteriophages. This family is characterized by having very short, noncontractile tails.

There are at least 74 species in this family.

Virology[edit]

The viron is nonenveloped with a head-tail structure. There are 9 structural proteins.

The head is ~60 nanometers (nm) in diameter, consists of 72 capsomers and is icosahedral with a T = 7 symmetry. The head protein has a molecular mass of ~38 kiloDaltons and is present in 460 copies per virion.

The tail is non-contractile and has 6 short subterminal fibers. It is thick and rod-shaped and built of stacked disks. The maximum length is ~17 nm.

The double stranded DNA genome is linear ~40-42 kilobases in length and encodes ~55 genes. The guanine + cytosine content is ~50%. It has terminally redundant sequences and is nonpermuted. By weight, the genome constitutes ~50% of the viron.

The genome encodes 9 structural proteins, an adenylated transferase B type DNA polymerase and an RNA polymerase. Three internal proteins constitute the polymerase complex.

Two classes of genes are recognized (early and late). This classification is based on the timing of transcription that is temporally regulated. Genes with related functions are clustered together. Genome replication is bidirectional.

In general, these viruses tend to be lytic rather than lysogenic.

Taxonomy[edit]

Genera within this family have ~40% homology between corresponding proteins. Subfamiles have ~20% homology between corresponding proteins.

This family is divided into two subfamiles (Autographivirinae and Picovirinae) and a number of genera awaiting classification into subfamilies.

Other genera awaiting classification into subfamilies:

References[edit]