2GAG:
reference: Heterotetrameric sarcosine oxidase: structure of a diflavin metalloenzyme at 1.85 a resolution., Chen ZW, Hassan-Abdulah A, Zhao G, Jorns MS, Mathews FS, J Mol Biol. 2006 Jul 28;360(5):1000-18. Epub 2006 Jun 15. PMID: 16820168

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