Homologous Superfamily

Glycoprotein E central domain, subdomain 2 (IPR013756)

Short name: GlyE_cen_dom_subdom2


Flaviviruses are small, enveloped RNA viruses that use arthropods such as mosquitoes for transmission to their vertebrate hosts, and include Yellow fever virus (YFV), West Nile virus (WNV), Tick-borne encephalitis virus, Japanese encephalitis virus (JE) and Dengue virus 2 viruses [PMID: 15378043]. Flaviviruses consist of three structural proteins: the core nucleocapsid protein C (IPR001122), and the envelope glycoproteins M (IPR000069) and E. Glycoprotein E is a class II viral fusion protein that mediates both receptor binding and fusion. Class II viral fusion proteins are found in flaviviruses and alphaviruses, and are structurally distinct from class I fusion proteins from influenza virus and HIV.

Glycoprotein E is comprised of three domains: domain I (dimerisation domain) is an 8-stranded beta barrel, domain II (central domain) is an elongated domain composed of twelve beta strands and two alpha helices, and domain III (immunoglobulin-like domain) is an IgC-like module with ten beta strands. Domains I and II are intertwined [PMID: 7753193]. Domain II can be divided into two structural components, both of which comprise alpha-beta sandwich folds, nominally referred to as regions 1 and 2. This entry represents region 2 of domain II, the central domain.

The glycoprotein E dimers on the viral surface re-cluster irreversibly into fusion-competent trimers upon exposure to low pH, as found in the acidic environment of the endosome. The formation of trimers results in a conformational change in the hinge region of domain II, a key structural element that opens a ligand-binding hydrophobic pocket at the interface between domains I and II. The conformational change results in the exposure of a fusion peptide loop at the tip of domain II, which is required in the fusion step to drive the cellular and viral membranes together by inserting into the membrane [PMID: 12759475].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.