Hémagglutinine

The hémagglutinine (ha) is an antigenic glycoprotéine present at the surface of the Virus of the Grippe, and is responsible for the fixing of the viral particle to a receiver located on the cell target. The name hémagglutinine comes from the faculty of the Protéine to agglomerate the hematic érythrocyte S (Nelson 2005).

Sub-types

There are 19 types different of antigens ha. These sub-types are numbered of H1 with H19. H16 was recently discovered on the viruses of influenza, isolated on Goéland S with black head from Sweden and Norway (Fouchier 2005). One finds the three first hémagglutinines H1, H2 and H3 on the pathogenic viral strains of human Grippe.

Functions and mechanisms of action

The ha has two functions principales :
  1. recognition of the target cells vertebrate, accomplished during fixing to the receiving S of these cells containing of the sialic Acid (cells of the pulmonary epithelium).
  2. the fusion of the membranes endosomales hosts and viral (White 1997), achieved by the recruitment of molecules ha by the site host of fusion, where some of these molecules undertake deteriorations of conformation destabilizing the lipidic double-layer host, which leads to the joint formation of an intermediary of fusion associating the two lipidic double-layers.
As of operated fusion, the joint cellular membrane is retightened, the viral hull opens directly on the cytoplasm host, and the viral genetic material is injected into the host cell where it will be able to reproduce.

Structure

The ha is an integral Glycoprotéine homotrimeric of the membrane. Of cylindrical form , it measures approximately 135  Å length. The three identical monomers which constitute the ha are grouped in a central spiral alpha-helicoid   ; three spherical heads contain the sites of fixing of the target acid sialic.

Monomers ha are initially synthesized like Précurseur S, then are then glycosylatés and cut out into two Polypeptide S more petits : sub-units HA1 and HA2. Each of three monomers ha consists of a long helicoid chain, anchored to the membrane by HA2 and surmounted by a broad globule HA1.

References

  • University of Strasbourg
  • Fouchier R.A.M., Munster V., Wallensten A. and Al , 2005. Characterization off has Novell influenza has virus hemagglutinin subtype (H16) obtained from black-headed gulls'. Appeared in J. Virology. vol. 79, n°5, pp.2814-22
  • Nelson D.L and Cox M.M. , 2005. Lehninger' S Principles off Biochemistry , 4 {E}} edition, WH Freeman, New York, NY, the USA.
  • Weiss W.I., Brünger A.T., Skehel J.J and Al , 1990. Refinement off the influenza virus hemagglutinin by simulated annealing . Appeared in J. Molecular Biology vol. 212, pp.737-761
  • White J.M., Hoffman L.R., Arevalo J.H. and Al , 1997. Attachment and entry off influenza virus into host concealments. Pivotal roles off hemagglutinin . Appeared in Structural Biology off Viruses , Chiu W., Burnett R.M. and Garcea R.L., editors. Oxford University Near, NY, the USA. pp.80-104

See too

Random links:-352 | 1901 | Dominion (manga) | Asprières | Lubatchov | Andre Soulas | Étudiant_Pugwash_Etats-Unis