Tectivirus
| Tectiviridae | |
|---|---|
 | |
| CryoEM model of Enterobacteria phage PRD1 capsid. PDB entry 1gw7[1] | |
| Virus classification | |
| Group: | Group I (dsDNA) |
| Family: | Tectiviridae |
| Genus: | Tectivirus |
| Species | |
|
Bacillus anthracis phage AP50 | |
The Tectiviridae is a family of double-stranded DNA viruses that infect bacteria and archea. Tectiviridae have no head-tail structure, but are capable of producing tail-like tubes of ~ 60×10 nm upon adsorption or after chloroform treatment. The name is derived from Latin tectus (meaning 'covered').
There is a single genus in this family—genus Tectivirus.
The type species is Enterobacteria phage PRD1.
Virology
The virions of Tectiviridae species are non-enveloped, icosahedral and display a pseudo T=25 symmetry. The capsid has two layers. The outer layer is a protein structure of 240 capsid proteins trimers, and the inner one is a proteinaceous lipid membrane which envelopes the virus genome. Apical spikes extending about 20 nanometers (nm) protrude from the icosahedrons vertices.
The genome is a single molecule of linear double-stranded DNA of 15 kilobases in length. It forms a tightly packed coil and encodes several structural proteins. It encodes about 30 proteins that are transcribed in operons. At least 9 structural proteins are present in the viron.
The genome is about 66 megaDaltons in weight and constitutes 14–15% of the virion by weight. Lipids constitute a further 15% by weight. Carbohydrates are not present.
Life cycle
After adsorbion to the host cell surface the virion extrudes a tail-tube structure through a vertex for genome delivery into the host.
Capsid proteins polymerize around a lipoprotein vesicle translocated in the cytoplasm by virion assembly factors.
Mature virons are released by lysis, which, in the case of PRD1, is achieved with the aid of virus-encoded lysis machinery consisting of four proteins: P15 (endolysin),[2] P35 (holin),[3] P36 and P37 (homologues of the Rz/Rz1 proteins of phage lambda).[4]
References
- ↑ San Martín, C; Huiskonen, JT; Bamford, JK; Butcher, SJ; Fuller, SD; Bamford, DH; Burnett, RM (2002). "Minor proteins, mobile arms and membrane-capsid interactions in the bacteriophage PRD1 capsid". Nature structural biology 9 (10): 756–63. doi:10.1038/nsb837. PMID 12219080.
- ↑ Caldentey J, Hänninen AL, Bamford DH (1994). "Gene XV of bacteriophage PRD1 encodes a lytic enzyme with muramidase activity". Eur J Biochem 225 (1): 341–346. doi:10.1111/j.1432-1033.1994.00341.x. PMID 7925454.
- ↑ Rydman PS, Bamford DH (2003). "Identification and mutational analysis of bacteriophage PRD1 holin protein P35". J Bacteriol 185 (13): 3795–3803. doi:10.1128/JB.185.13.3795-3803.2003. PMC 161566. PMID 12813073.
- ↑ Krupovic M, Cvirkaite-Krupovic V, Bamford DH (2008). "Identification and functional analysis of the Rz/Rz1-like accessory lysis genes in the membrane-containing bacteriophage PRD1". Mol Microbiol 68 (2): 492–503. doi:10.1111/j.1365-2958.2008.06165.x. PMID 18366440.
ICTVdB—The Universal Virus Database ICTVdB Management (2006). 00.068. Tectiviridae. In: ICTVdB - The Universal Virus Database, version 3. Büchen-Osmond, C. (Ed), Columbia University, New York, USA
Virus Taxonomy: Eighth Report of the International Committee on Taxonomy of Viruses H.V. Van Regenmortel, D.H.L. Bishop, M. H. Van Regenmortel, Claude M. Fauquet (Eds)