Cys4 (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption The crystal structure of the Csy4 enzyme (blue) bound to a crRNA molecule (orange). The crRNA contains nucletotide sequences that match those of foreign DNA from a virus or plasmid, enabling it to target and silence the invaders. Credit Image courtesy of the Doudna group 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.