2ALX:
reference: Structure of Escherichia coli ribonucleotide reductase R2 in space group P6122., Sommerhalter M, Saleh L, Bollinger JM Jr, Rosenzweig AC, Acta Crystallogr D Biol Crystallogr. 2005 Dec;61(Pt 12):1649-54. Epub 2005, Nov 19. PMID: 16301799

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