2YNJ:
reference: Protein secondary structure determination by constrained single-particle cryo-electron tomography., Bartesaghi A, Lecumberry F, Sapiro G, Subramaniam S, Structure. 2012 Dec 5;20(12):2003-13. doi: 10.1016/j.str.2012.10.016. PMID: 23217682

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