3C3F:
reference: Interplay among side chain sequence, backbone composition, and residue rigidification in polypeptide folding and assembly., Horne WS, Price JL, Gellman SH, Proc Natl Acad Sci U S A. 2008 Jul 8;105(27):9151-6. Epub 2008 Jun 27. PMID: 18587049

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