Zhu et al. performed genetic, biochemical, and structural experiments to reveal how this large protein complex is formed and to understand how it functions to protect cells from intracellular infection. Cryo–electron tomography revealed that dimers of GBP1 form an even coating on bacteria, and medium-resolution reconstructions suggested that an extended conformation allows the protein to insert into and disrupt the bacterial outer membrane. —Michael A. Funk and Stella M. Hurtley.
