3FKY:
reference: Crystal structure of Saccharomyces cerevisiae glutamine synthetase Gln1 suggests a nanotube-like supramolecular assembly., He YX, Gui L, Liu YZ, Du Y, Zhou Y, Li P, Zhou CZ, Proteins. 2009 Jul;76(1):249-54. PMID: 19322816

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