3D Crystal Structure of C. diff Toxin B (IMAGE) University of California - Irvine Caption On the left is an illustration of the deadly C. diff bacteria as seen under a microscope. The image on the right, resembling a question mark, is the first three-dimensional crystal structure of TcdB holotoxin, secreted by C. diff. TcdB is illustrated as a ribbon model superimposed with a transparent molecular surface. This structure provides a blueprint to develop new therapeutics and vaccines for the treatment of CDI. Credit UCI School of Medicine 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.