Tet Enzyme with DNA (IMAGE) Emory Health Sciences Caption This is the structure of the Tet enzyme with DNA. Note the purple ball at the active site, close to which one DNA base is flipped out of the double helix. Also note the degree to which the double helix is bent. Credit Xiaodong Cheng, Emory University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.