1OU5:
reference: Crystal structure of the human CCA-adding enzyme: insights into template-independent polymerization., Augustin MA, Reichert AS, Betat H, Huber R, Morl M, Steegborn C, J Mol Biol 2003 May 16;328(5):985-94. PMID: 12729736

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