Is hemagglutinin a fusion protein?
Is hemagglutinin a fusion protein?
Influenza virus hemagglutinin, vesicular stomatitis virus G protein, and retrovirus envelope proteins are well-characterized viral glycoproteins that participate in attachment and fusion.
How many amino acids are in hemagglutinin?
328 amino acids
The HA1 subunit (328 amino acids) has a globular form outside the virus’ membrane: it is composed by an eight-stranded beta-sheet, associated with a little alpha-helix, separating the strands 3 and 4.
What kind of protein is hemagglutinin?
glycoprotein
Structure. The hemagglutinin has a cylindrical shape and is a small protein (13 nanometers long). It’s a glycoprotein formed by three identical monomer subunits, together known as a homotrimer.
What is the trigger for influenza virus fusion protein?
The relatively simple trigger for influenza virus HA is proton binding, leading to a transition when the endosomal pH falls below about 5.5; for the HIV-1 envelope protein, receptor (CD4) binding induces an initial conformation change that exposes a co-receptor binding surface, and only when co-receptor (CXCR4 or CCR5) …
What is the purpose of hemagglutinin?
The hemagglutinin(HA) of influenza virus is a major glycoprotein and plays a crucial role in the early stage of virus infection: HA is responsible for binding of the virus to cell surface receptors, and it mediates liberation of the viral genome into the cytoplasm through membrane fusion.
What is the structure of hemagglutinin?
Hemagglutinin consists of a globular head and a stem. The globular head consists of three chains, Chains A, C, and E. The stem of the protein consists of three chains as well, Chains B, D, and F.
How many subunits does hemagglutinin have?
Hemagglutinin contains three identical monomers from an alpha helix coil, which hold the sialic acid binding sites.
What does hemagglutinin attach to?
The viral hemagglutinin attaches to host cells via sialic acid containing receptors. Viral replication occurs in both upper and lower respiratory tracts.
Is hemagglutinin a lectin?
HA is the lectin that mediates the viral entry in the host cell. Once the virus has been internalized and replicated by the host cell machinery, newly formed virions bud from the cell and remain bound to the membrane sialic acids by means of their interaction with HA.
How do viral fusion proteins work?
Certain viral fusion proteins induce cell-cell fusion when expressed on the cell surface as a consequence of infection, and cell-cell fusion can contribute to viral spread, viruluence, persistence, and other untoward consequences (Corcoran et al., 2006; Cousens et al., 2007; Duelli and Lazebnik, 2007; Garg et al., 2007 …
Is hemagglutinin a virulence factor?
Molecules known as virulence factors are produced by bacteria, viruses, and fungi to help them to infect host cells. One of virulence factors found in the influenza A viruses is hemagglutinin (HA).
Is hemagglutinin a matrix protein?
Influenza virus hemagglutinin and neuraminidase, but not the matrix protein, are required for assembly and budding of plasmid-derived virus-like particles. J Virol.