Tropoelastin Illustration (image) University of Washington Caption This is an illustration of the molecular structure of tropoelastin, the smallest unit of the protein elastin. Credit Matthew Zelisko, University of Houston Usage Restrictions Photo credit required. 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.