6LFH:
reference: Efficient Chemical Protein Synthesis using Fmoc-Masked N-Terminal Cysteine in Peptide Thioester Segments., Kar A, Mannuthodikayil J, Singh S, Biswas A, Dubey P, Das A, Mandal K, Angew Chem Int Ed Engl. 2020 Apr 25. doi: 10.1002/anie.202000491. PMID: 32333711

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