Isolation of the influenza A HA2 C-terminal segment by combination of nonionic detergents.

Introduction Influenza A virus hemagglutinin (HA) is a transmembrane glycoprotein of the viral envelope which plays a central role in the delivery of the viral nucleocapsid into the host cell. HA ectodomain cleaved by enzyme bromelain was solved by X-ray crystallography. On the other hand, for the C-terminal anchoring segment which includes a transmembrane domain (TM) and a cytoplasmic tail (Fig. 1a) there is no 3D-structural information available, and data about its primary structure is insufficient. Another transmembrane glycoprotein of the envelope, neuraminidase (NA) is anchored by its N-terminal domain (Fig. 1b).