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.

Contents

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 whose 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