1NN2:
reference: Three-dimensional structure of the neuraminidase of influenza virus A/Tokyo/3/67 at 2.2 A resolution., Varghese JN, Colman PM, J Mol Biol 1991 Sep 20;221(2):473-86. PMID: 1920428

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).