6MGH:
reference: Smallest near-infrared fluorescent protein evolved from cyanobacteriochrome as versatile tag for spectral multiplexing., Oliinyk OS, Shemetov AA, Pletnev S, Shcherbakova DM, Verkhusha VV, Nat Commun. 2019 Jan 17;10(1):279. doi: 10.1038/s41467-018-08050-8. PMID: 30655515

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