Protein Mediation (IMAGE) St. Jude Children's Research Hospital Caption Work led by St. Jude Children's Research Hospital scientists has identified a new function for the acetyl group attached to N-terminal end of protein. This modification occurs on between 30 and 80 percent of proteins, although its function has been generally unknown. The research focused on the interaction of the Ubc12 and Dcn1 proteins but investigators said the same mechanism might also be at work in thousands of other protein interactions. This image shows a portion of the crystal structure of the Ubc12-Dcn1 complex. The spheres represent the acetyl group and the methionine amino acid at the N-terminus of Ubc12 to which it is attached, and two other surrounding amino acids. The mesh represents the pocket on Dcn1 where the acetyl-methionine fits like a key in a key-hole. Researchers showed this connection served to accelerate the work of the Ubc12-Dcn1 complex, which helps regulate cell division. Notably, Dcn1 has been linked to cancer. Credit Image courtesy of Science/AAAS Usage Restrictions Image may only be used with appropraite credit. 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.