1FMF:
reference: A protein pre-organized to trap the nucleotide moiety of coenzyme B(12): refined solution structure of the B(12)-binding subunit of glutamate mutase from Clostridium tetanomorphum., Hoffmann B, Tollinger M, Konrat R, Huhta M, Marsh EN, Krautler B, Chembiochem. 2001 Sep 3;2(9):643-55. PMID: 11828501

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