Alphatroma virus

from Wikipedia, the free encyclopedia
Alphatroma virus
Systematics
Classification : Viruses
Area : unclassified
Empire : unclassified
Phylum : unclassified
Class : unclassified
Order : unclassified
Family : Tristromaviridae
Genre : Alphatroma virus
Taxonomic characteristics
Genome : dsDNA linear
Baltimore : Group 1
Symmetry : helical
Cover : available
Scientific name
Alphatroma virus
Left
NCBI  Taxonomy: 341939
ViralZone ( ExPASy , SIB): 8557 (new) ,
171 (old)
ICTVdB Virus Code : 00.038.0.01

The genus Alphatristromavirus (formerly Alphalipothrixvirus ) is a virus genus within the family of Tristromaviridae , the members of which comprise elongated, enveloped bacteriophages with a double-stranded DNA (dsDNA) as a genome . The originally only species of the Alphatristromavirus genus , Thermoproteus tenax virus 1 (TTV-1), has now been supplemented by a second species, Pyrobaculum filamentous virus 1 (PFV-1). It has the Archaea Thermoproteus tenax as its host , which asthermophilic organism is found in hot volcanic springs and geysers . The genus was previously placed in the Lipothrixviridae family , but was regrouped by ICTV due to inconsistent genome sequences .

morphology

The virus particles (virions) of Thermoproteus Tenax virus 1 appear under the electron microscope as straight, inflexible rods with a length of 410 nm and a thickness of 38 nm. Asymmetrical thickenings are located at both ends. Two structural proteins bound to the DNA strand (VP1 and VP2 or TP1, TP2) form a helical capsid , which is surrounded by a lipid-containing virus envelope . In contrast to normal cellular lipids, this shell consists primarily of glycerol tetraether lipids, as can also be found in the special cell membrane of the archaea. The phosphate residues of these phospholipids are directed inwards, while the glycosyl residues form the outside of the virus envelope. The viral envelope protein VP3 (TP3) is also embedded in the envelope . An additional, but not precisely localized, structural protein VP4 (TP4) is located in the virion. A virion has a molar mass of about 3.3 x 10 8 Da and shows a density of 1.25 g / cm³ on density gradient centrifugation in cesium chloride . They are still completely stable at 100 ° C; after autoclaving at 120 ° C, some of the viruses are still able to reproduce.  

Genome

The TTV-1 DNA has a length of about 15,900  base pairs (bp), of which only about 13,700 bp have been sequenced so far. In addition to the open reading frames (ORF) for the four structural proteins, two more for functional proteins (TPX and PTn) could be identified; the meaning of most of the genes has not yet been clarified. Almost all of the larger, identified ORFs are on one strand of DNA. When translating its genetic information, the TTV-1 does not use the usual code of eukaryotic cells, but rather those special codons that are also used by its host.

Systematics

System according to ICTV as of November 2018, supplemented by subtypes:

  • Genus Alphalipothrixvirus (formerly Alphalipothrixvirus )
  • Species Thermoproteus tenax virus 1 (en. Thermoproteus tenax virus 1 , TTV-1)
  • Subtype Thermoproteus tenax virus 1 strain KRA1
  • Subtype Thermoproteus tenax virus 1 strain VT3
  • Species Pyrobaculum-filamentous-virus 1 (en. Pyrobaculum filamentous virus 1 , PFV-1, type species)

swell

  • K. Stedman et al. : Genus Alphalipothrixvirus . In: CM Fauquet, MA Mayo et al. : Eighth Report of the International Committee on Taxonomy of Viruses , London, San Diego, 2004 pp. 96-98
  • H. Neumann, V. Schwass, C. Eckerskorn, W. Zillig: Identification and characterization of the genes encoding three structural proteins of the Thermoproteus tenax virus TTV-1 . Mol. Gen. Genet. (1989) 217: pp. 105-110 PMID 2505050

Individual evidence

  1. ↑ ICTV : dsDNA Viruses> Tristromaviridae , October 2018
  2. ↑ Alternative genetic code for bacteria and plant plastids see The Bacterial, Archaeal and Plant Plastid Code (transl_table = 11)
  3. ↑ ICTV : Master Species List (# 33) from autumn 2018

Web links