Influenza A H5N1 (A/Hong Kong/483/1997) Hemagglutinin / HA Protein (His Tag)

The influenza viral Hemagglutinin (HA) protein is a homotrimer with a receptor binding pocket on the globular head of each monomer.HA has at least 18 different antigens. These subtypes are named H1 through H18.HA has two functions. Firstly, it allows the recognition of target vertebrate cells, accomplished through the binding to these cells' sialic acid-containing receptors. Secondly, once bound it facilitates the entry of the viral genome into the target cells by causing the fusion of the host endosomal membrane with the viral membrane. The influenza virus Hemagglutinin (HA) protein is translated in cells as a single protein, HA, or hemagglutinin precursor protein. For viral activation, hemagglutinin precursor protein (HA) must be cleaved by a trypsin-like serine endoprotease at a specific site, normally coded for by a single basic amino acid (usually arginine) between the HA1 and HA2 domains of the protein. After cleavage, the two disulfide-bonded protein domains produce the mature form of the protein subunits as a prerequisite for the conformational change necessary for fusion and hence viral infectivity.

At Leading Biology, the biological activity of a recombinant protein is routinely measured using a bioassay, e.g. chemotaxis or cell proliferation assay, enzyme assay, or a functional ELISA. When a recombinant protein is an enzyme, specific activity is derived from an enzymatic assay. Each enzyme is tested for potency by cleavage of a substrate. We are in the process of updating the biological activity data. If you have any questions regarding this update, please feel free to contact our technical support team.

Lyophilized from sterile PBS, pH 7.4. Please contact us for any concerns or special requirements. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween 80 are added as protectants before lyophilization. Please refer to the specific buffer information in the hard copy of CoA.

The secreted recombinant influenza A H5N1 HA (A/Hong Kong/483/1997 (H5N1) ) comprises 524 amino acids and has a predicted molecular mass of 59.7 kDa. As a result of glycosylation, it migrates as an approximately 65-75 kDa band in SDS-PAGE under reducing conditions.

In general, recombinant proteins are provided as lyophilized powder which are shipped at ambient temperature. Bulk packages of recombinant proteins are provided as frozen liquid. They are shipped out with blue ice unless customers require otherwise. Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.

A DNA sequence encoding the extracellular domain (Met 1-Gln 531) of the influenza A H5N1 hemagglutinin (A/Hong Kong/483/1997 (H5N1) ) (AAC32099.1), (HA1+HA2, uncleaved, cleavage site mutated (RRRKKR-TETR) was expressed, fused with a C-terminal polyhistidine tag.