5E6E:
reference: Crystal structure of carbonmonoxy sickle hemoglobin in R-state conformation., Ghatge MS, Ahmed MH, Omar AS, Pagare PP, Rosef S, Kellogg GE, Abdulmalik O, Safo MK, J Struct Biol. 2016 Jun;194(3):446-50. doi: 10.1016/j.jsb.2016.04.003. Epub 2016 , Apr 13. PMID: 27085422

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