2N8A:
reference: Structural Basis of Detection and Signaling of DNA Single-Strand Breaks by Human PARP-1., Eustermann S, Wu WF, Langelier MF, Yang JC, Easton LE, Riccio AA, Pascal JM, Neuhaus D, Mol Cell. 2015 Dec 3;60(5):742-54. doi: 10.1016/j.molcel.2015.10.032. Epub 2015, Nov 25. PMID: 26626479

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