4FH5:
reference: Crystal structures of the Cid1 poly (U) polymerase reveal the mechanism for UTP selectivity., Lunde BM, Magler I, Meinhart A, Nucleic Acids Res. 2012 Aug 9. PMID: 22885303

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