Escherichia Virus HK97

from Wikipedia, the free encyclopedia
Escherichia Virus HK97
BacteriophageHK97.jpg

TME image of a virus particle from Escherichia virus HK97

Systematics
Classification : Viruses
Area : Duplodnaviria
Empire : Heunggongvirae
Phylum : Uroviricota
Order : Caudovirales
Family : Siphoviridae
Genre : Hendrix virus
Type : Escherichia Virus HK97
Taxonomic characteristics
Genome : dsDNA linear
Baltimore : Group 1
Symmetry : icosahedral, tailed
Cover : no
Scientific name
Escherichia virus HK97
Short name
HK97
Left
NCBI  Taxonomy: 37554
ICTV Taxon History: 201851071

Escherichia virus HK97 ( acronym HK97 ) is a species of bacterial virus . Their hosts are, according to the name, bacteria of the genus Escherichia (Escherichia), ie coli bacteria (bacterial species E. coli ) and relatives. The viruses of this species are therefore also classified as bacteriophages (or phages for short), hence the old name bacteriophage HK97 . The acronym HK stands for Hong Kong , the place where these viruses were first isolated. Such as the Lambda phage and other phages lamboide (genus lambda virus ) has HK97 a double-stranded DNA - genome . Due to major genetic differences, the species is no longer classified in this, but in a genus Hendrixvirus of the same virus family Siphoviridae , the type species of which is HK97. Together with other phages with a head-to-tail structure, the Siphoviridae belongs to the order Caudovirales . This bacterial virus must be distinguished from the giant Hokovirus (HKV or HokV) and the human pathogenic genus Tetraparvovirus , formerly also known as the Hong Kong virus or Hokovirus .

Propagation cycle

The virus particles ( virions ) of HK97 have a head-to-tail structure: The head (the actual capsid ) houses the genetic material , here double-stranded DNA (dsDNA). After docking with the bacterial host cell, it is injected through the tail into the host through the tail. In detail, the processes are as follows:

The capsid protein gp5 from HK97 crosslinks during maturation to form a linked chain mail- like structure. The bacteriophage undergoes a maturation process during the DNA packaging in the capsid, during which it expands by almost 5  nm and its geometry changes from spherically symmetrical to icosahedral symmetrical.

The assembly ( assembly ) of the virus particles (virions) begins with the self-organization of the capsid protein gp5 to form pentamers and hexamers . The protease gp4 cleaves gp5 at its amino terminus . The subsequent addition of a so-called portal protein ( English portal protein , here labeled gp3) causes conformational changes leading to the formation of a Prohead- or Procapsid structure - which is not filled with genetic material Kapsidkopf - lead. Further conformational changes and the cross-linking of gp5 monomers cause further capsid maturation and lead to the formation of a finished phage head. Unlike most other viruses with head-to-tail structure (order Caudovirales ) is for the capsid assembly no scaffolding protein ( English scaffolding protein (would such the Procapsid like a) require scaffolding support and after packaging mostly mined).

SHE

Superinfection exclusion (SIE) is a phenomenon in which an already existing viral infection (initial infection) in a competitive situation prevents a secondary infection with the same or a closely related virus. This effect is therefore a phenotype of the virus in question, but in many cases it is still poorly understood. SHE can reflect some kind of antiviral state in the infected cell.

There are a number of phages (i.e., bacterial viruses) that encode proteins to reach SIE. These viral proteins can interfere with the release of DNA into the host cytoplasm or modify the entry receptor . They can also act as inhibitors of viral peptidoglycan degradation enzymes - with which phages perforate the wall of the bacterial cell - and thus prevent the entry of further, newly arriving phages. HK97 with its SIE protein gp15 also belongs to this group of phages.

Systematics

The group of HK97-like phages was previously assigned to the genus of lambdoid phages ( Lambdalikevirus , today Lambdavirus ) due to morphological similarities . Based on genetic analyzes, the ICTV has meanwhile elevated this group to the rank of an independent genus. The current generic name Hendrixvirus honors the virologist Roger W. Hendrix, who has made a special contribution to researching these phages.

  • Genus Hendrixvirus (obsolete Hk97virus , HK97-like viruses )
  • Species Escherichia virus HK022 (Enterobacteria Phage HK022)
  • Species Escherichia virus HK75 with Escherichia phage HK75
  • Species Escherichia virus HK97 (Enterobacteria Phage HK97)
  • Species Escherichia virus HK106 with Enterobacteria phage HK106
  • Species Escherichia virus HK446 with Escherichia phage HK446
  • Species Escherichia virus HK542 with Escherichia virus HK542
  • Species Escherichia virus HK544 with Escherichia phage HK544
  • Species Escherichia virus HK633 with Escherichia phage HK633
  • Species Escherichia virus mEp234 with Escherichia phage mEp234
  • Species Escherichia virus mEpX1 with Escherichia phage mEpX1
  • Species Escherichia virus mEpX2 with Escherichia phage mEpX2
unclassified candidates to the genus Hendrixvirus :
  • Species " Enterobacteria phage HK140 "
  • Species " Enterobacteria phage mEp235 "
  • Species " Escherichia phage ECP1 "

Individual evidence

  1. ↑ a b c ICTV: ICTV Taxonomy history: Enterobacteria phage T4 , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
  2. ↑ a b ICTV: ICTV Master Species List 2018b.v2 MSL # 34v
  3. ↑ Charlotte Helgstrand, William R. Wikoff, Robert L. Duda, Roger W. Hendrix, John E. Johnson, Lars Liljas: The Refined Structure of a Protein Catenane: The HK97 Bacteriophage Capsid at 3.44Å Resolution . In: Journal of Molecular Biology . 334, No. 5, December 1, 2003, pp. 885-899. doi : 10.1016 / j.jmb.2003.09.035 . PMID 14643655 .
  4. ^ Roger W. Hendrix, John E. Johnson: Bacteriophage HK97 capsid assembly and maturation. . In: Advances in Experimental Medicine and Biology . 726, 2012, pp. 351-363. doi : 10.1007 / 978-1-4614-0980-9_15 . PMID 22297521 .
  5. ↑ Robert L. Duda, K. Martincic, Roger W. Hendrix: Genetic basis of bacteriophage HK97 prohead assembly . In: J. Mol. Biol. . 247, No. 4, 1995, pp. 636-647. doi : 10.1006 / jmbi.1994.0169 . PMID 7723020 .
  6. ^ B. Oh, C. L. Moyer, Roger W. Hendrix, Robert L. Duda: The delta domain of the HK97 major capsid protein is essential for assembly . In: Virology . 456–457, 2014, pp. 171–178. doi : 10.1016 / j.virol.2014.03.022 . PMID 24889236 . PMC 4044616 (free full text).
  7. ↑ Knut J. Heller, Horst Neve: Superinfection exclusion and DNA injection in Siphoviridae phages , Biospektrum Heft 1 (2014), pp. 26-29
  8. ↑ a b SIB: Superinfection exclusion , to: ExPASy ViralZone
  9. ↑ Compare also Influenza A and rhinoviruses : Nadja Podbregar: Influenza protects against colds - researchers show for the first time the interaction of two viral pathogens : scinexx.de of December 17, 2019
  10. ↑ NCBI: Hendrix virus (genus)
  11. ↑ NCBI: unclassified Hendrix virus

Web links