Sortylation (IMAGE) Technical University of Munich (TUM) Caption The researchers equipped a cellular protein (gray) with a modified lysine amino acid building block (pink), to which the bacterial enzyme sortase (yellow) transmits a ubiquitin molecule (blue). Credit K. Lang / TUM 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.