– Mediates the viral entry into the host cell together with fusion/F protein. Attaches the virus to sialic acid-containing cell receptors and thereby initiates infection. Binding of HN protein to the receptor induces a conformational change that allows the F protein to trigger virion/cell membranes fusion.; Neuraminidase activity ensures the efficient spread of the virus by dissociating the mature virions from the neuraminic acid containing glycoproteins. Newcastle disease virus (NDV) (strain Her/33) Hemagglutinin-neuraminidase Protein (His) is expressed in E. coli expression system with N-6xHis tag. The predicted molecular weight is 45.1 kDa and the accession number is P35741.