Studies on the Structure of the Hemagglutinin

Abstract

There are two procedures in common use for the isolation of the hem agglutinin — one involves dissolution of virus particles with detergents, the other their digestion with proteases. As discussed elsewhere in this volume the former procedure yields the intact membrane glycoprotein (HA) which aggregates in the absence of detergent and, therefore, retains the ability to agglutinate erythrocytes. On the other hand, proteolytic digestion and more specifically bromelain digestion of virus particles (Brand and Skehel, 1972) results in the release of a soluble glycoprotein (BHA) which does not aggregate in detergent-free solution and is composed of hemagglutinin subunits which are modified at their carboxyl termini (Skehel and Waterfield, 1975). This report contains results of initial analyses 9f the three dimensional structure of the hemagglutinins prepared by these two different procedures and concerns X-ray diffraction studies of crystalline BHA and circular dichroism spectroscopy of HA and BHA.