1FYB:
reference: The solution structure of C1-T1, a two-domain proteinase inhibitor derived from a circular precursor protein from Nicotiana alata., Schirra HJ, Scanlon MJ, Lee MC, Anderson MA, Craik DJ, J Mol Biol 2001 Feb 9;306(1):69-79. PMID: 11178894

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