The image is a computational model of a CRISPR-associated protein complex called Cascade, from the bacterium E. coli. Bacteria use short DNA sequences (CRISPR) to identify attacking viruses. The model here shows proteins as colored clumps that have recognized an unwound piece of viral DNA, nestled in a channel in the complex. The model, created by Douglas Renfrew of the Flatiron Institute’s Center fo Computational Biology, is based on the paper “Crystal Structure of a CRISPR RNA–Guided Surveillance Complex Bound to a ssDNA Target,” by Sabin Mulepati, Annie Héroux, and Scott Bailey, published in Science in 2014. The molecule is listed in the Protein Data Bank as 4QYZ.