3K7D:
reference: Structure of the Adenylylation Domain of E. coli Glutamine Synthetase Adenylyl Transferase: Evidence for Gene Duplication and Evolution of a New Active Site., Xu Y, Carr PD, Vasudevan SG, Ollis DL, J Mol Biol. 2009 Dec 21. PMID: 20026075

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