5HTB:
reference: Co-crystal structures of the protein kinase haspin with bisubstrate inhibitors., Lavogina D, Kestav K, Chaikuad A, Heroven C, Knapp S, Uri A, Acta Crystallogr F Struct Biol Commun. 2016 May 1;72(Pt 5):339-45. doi:, 10.1107/S2053230X16004611. Epub 2016 Apr 22. PMID: 27139824

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