H5N1 HA (A/Hong Kong/483/97) His Tag Protein

Neuraminidase (NA)and hemagglutinin (HA) are major membrane glycoproteins found on the surface ofinfluenza virus. Hemagglutinin binds to the sialic acid-containing receptors onthe surface of host cells during initial infection and at the end of an infectiouscycle. Hemagglutinin also plays a major role in the determination of host rangerestriction and virulence. As a class I viral fusion protein, hemagglutinin isresponsible for penetration of the virus into the cell cytoplasm by mediatingthe fusion of the membrane of the endocytosed virus particle with the endosomalmembrane. Binds to sialic acid-containing receptors on the cell surface,bringing about the attachment of the virus particle to the cell. Thisattachment induces virion internalization either through clathrin-dependentendocytosis or through clathrin- and caveolin-independent pathway. Plays amajor role in the determination of host range restriction and virulence. ClassI viral fusion protein. Responsible for penetration of the virus into the cellcytoplasm by mediating the fusion of the membrane of the endocytosed virusparticle with the endosomal membrane. Low pH in endosomes induces anirreversible conformational change in HA2, releasing the fusion hydrophobicpeptide. Several trimers are required to form a competent fusion pore.