4FAB:
reference: Three-dimensional structure of a fluorescein-Fab complex crystallized in 2-methyl-2,4-pentanediol., Herron JN, He XM, Mason ML, Voss EW Jr, Edmundson AB, Proteins 1989;5(4):271-80. PMID: 2508085

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