1QK1:
reference: Crystal structure of human ubiquitous mitochondrial creatine kinase., Eder M, Fritz-Wolf K, Kabsch W, Wallimann T, Schlattner U, Proteins. 2000 May 15;39(3):216-25. PMID: 10737943

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