4ULL:
reference: Solution structure of the carbohydrate-binding B-subunit homopentamer of verotoxin VT-1 from E. coli., Richardson JM, Evans PD, Homans SW, Donohue-Rolfe A, Nat Struct Biol. 1997 Mar;4(3):190-3. PMID: 9164458

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