4K5C:
reference: From DARPins to LoopDARPins: novel LoopDARPin design allows the selection of low picomolar binders in a single round of ribosome display., Schilling J, Schoppe J, Pluckthun A, J Mol Biol. 2014 Feb 6;426(3):691-721. PMID: 24513107

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