AbyU Enzyme (image) University of Bristol Share Print E-Mail Caption The antibiotic abyssomycin formed in the cavity of AbyU, a natural Diels-Alder enzyme with a simple beta-barrel fold. The orange spheres indicate the atoms involved in the newly formed bonds. Credit P. Race Usage Restrictions Only to be used to illustrate the accompanying story. Share Print E-Mail 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.