4QPX:
reference: Structure of a backtracked state reveals conformational changes similar to the state following nucleotide incorporation in human norovirus polymerase., Zamyatkin D, Rao C, Hoffarth E, Jurca G, Rho H, Parra F, Grochulski P, Ng KK, Acta Crystallogr D Biol Crystallogr. 2014 Dec 1;70(Pt 12):3099-109. doi:, 10.1107/S1399004714021518. Epub 2014 Nov 22. PMID: 25478829

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