3CBE:
reference: Development of a family of redox-sensitive green fluorescent protein indicators for use in relatively oxidizing subcellular environments., Lohman JR, Remington SJ, Biochemistry. 2008 Aug 19;47(33):8678-88. Epub 2008 Jul 25. PMID: 18652491

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