3RSR:
reference: Evaluating the therapeutic potential of a non-natural nucleotide that inhibits human ribonucleotide reductase., Ahmad MF, Wan Q, Jha S, Motea E, Berdis A, Dealwis C, Mol Cancer Ther. 2012 Oct;11(10):2077-86. doi: 10.1158/1535-7163.MCT-12-0199., Epub 2012 Aug 28. PMID: 22933704

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