Influenza, commonly known as “the flu”, is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae, the influenza viruses. The virus is divided into three main types (Influenza virus A, Influenza virus B, and Influenza virus C), which are distinguished by differences in two major internal proteins (hemagglutinin (HA) and neuraminidase (NA), which are the most important targets for the immune system. The type A viruses are the most virulent human pathogens among the three influenza types and cause the most severe disease. Influenza virus hemagglutinin (HA) is a trimer of identical subunits, each of which contains two polypeptides that result from proteolytic cleavage of a single precursor. The two polypeptides are designated HA1 and HA2. The HA2 monomer is a long helical chain, anchored into the membrane, and is “topped” by a “globule” of HA1. Cleavage of the precursor is essential for activation of membrane fusion potential and hence infectivity. For HAs of most subtypes, the site of cleavage is a single arginine residue, and cleavage occurs extracellularly by an as yet unidentified enzyme. The Puerto Rico strain isolated in 1934 is one of the most commonly used laboratory strains, and formed the basis of early influenza vaccines. The structure of HA has been reviewed by Gamblin and Skehel in 2010.
Recombinant protein corresponding to aa1-529 of Influenza A [A/Puerto Rico/8/1934 (H1N1)] Hemagglutinin (HA), fused to His-Tag at C-terminal, expressed in HEK293 cells.
Molecular Weight:~59kD
Storage and Stability:May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 6 months after receipt at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.