Corticovirus

Corticovirus
Virus classification
Group:	Group I (dsDNA)
Family:	Corticoviridae
Genus:	Corticovirus
Species
Pseudoalteromonas phage PM2

The Corticoviridae' is a family of phages with a double stranded DNA genome that infect bacteria. The name is derived from Latin cortex, corticis (meaning 'crust' or 'bark').

The family has a single genus - Corticovirus.

The type species is Alteromonas phage PM2 which is currently the only known species in this genus.

This family of viruses has been little studied and not much is known about it.

Virology

The virons consist of a round, icosahedral, non-enveloped capsid of a diameter of 60 nm and an internal lipid membrane located between outer and inner protein shell^[1]. The shells are composed of three layers which surfaces reveals a pattern with distinctive features^[2], including bush-like spikes protruding from the twelve vertices^[3].

The icosahedral capsid ( (T = 12 or 13) is 56 nanometers (nm) in diameter and is composed of 1200 P1 (spike) and 60 P2 (capsid) proteins. The pentameric receptor-binding spikes protrude from the 12 fivefold axes. The capsid encloses an internal lipid core containing the structural proteins P3 to P9.

Genome

The genome is not segmented, constitutes 13% of the virus's weight and contains a single molecule of circular, supercoiled, double-stranded DNA of 9.5-12 kilobases in length. The genome has a g + c content of 43%^[4]. It encodes ~21 proteins.

Transcription is organised into three operons.

Replication of the genome is via a rolling-circle mechanism.

Literature

1. ^ Kiveld, H.M., Kalkkinen, N. and Bamford, D.H. (2002). Bacteriophage PM2 has a protein capsid surrounding a spherical lipid-protein core. J. Virol., 76, 8169-8178.
2. ^ Kiveld, H.M., Männistö, R.H., Kalkkinen, N. and Bamford, D.H. (1999). Purification and protein composition of PM2, the first lipid-containing bacterial virus to be isolated. Virology, 262, 364-374.
3. ^ Harrison, S.C., Caspar, D.L., Camerini-Otero, R.D. and Franklin, R.M. (1971). Lipid and protein arrangement in bacteriophage PM2. Nat. New Biol., 229, 197-201.
4. ^ Männistö, R.H., Kivelä, H.M., Paulin, L., Bamford, D.H. and Bamford, J.K.H. (1999). The complete genome sequence of PM2, the first lipid-containing bacterial virus to be isolated. Virology, 262, 355-363.

External links

• Viralzone: Corticoviridae