6C0H:
reference: Substrate-assisted enzymatic formation of lysinoalanine in duramycin., An L, Cogan DP, Navo CD, Jimenez-Oses G, Nair SK, van der Donk WA, Nat Chem Biol. 2018 Oct;14(10):928-933. doi: 10.1038/s41589-018-0122-4. Epub 2018, Sep 3. PMID: 30177849

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