1CI6:
reference: Crystal structure of the CCAAT box/enhancer-binding protein beta activating transcription factor-4 basic leucine zipper heterodimer in the absence of DNA., Podust LM, Krezel AM, Kim Y, J Biol Chem 2001 Jan 5;276(1):505-13. PMID: 11018027

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