Structure of the catalytic and antigenic sites in influenza virus neuraminidase

Abstract
The catalytic sites of influenzae virus neuraminidase are located on the upper corners of the box-shaped tetramer that forms the head of the molecule. Antigenic determinants form a nearly-continuous surface across the top of the monomer encircling the catalytic site. Approximately the same number of amino acid sequence changes occurred in these determinants between 1968-1975 as occurred in the antigenic sites of influenza virus hemagglutinin in the same period.