2OOP:
reference: Probing the formation of stable tertiary structure in a model miniprotein at atomic resolution: determinants of stability of a helical hairpin., Neumoin A, Mares J, Lerch-Bader M, Bader R, Zerbe O, J Am Chem Soc. 2007 Jul 18;129(28):8811-7. Epub 2007 Jun 20. PMID: 17580866

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