6RMM:
reference: Phosphorylation-mediated interactions with TOPBP1 couple 53BP1 and 9-1-1 to control the G1 DNA damage checkpoint., Bigot N, Day M, Baldock RA, Watts FZ, Oliver AW, Pearl LH, Elife. 2019 May 28;8. pii: 44353. doi: 10.7554/eLife.44353. PMID: 31135337

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