Holin of bacteriophage lambda: structural insights into a membrane lesion.

The length of the infection cycle of double-stranded DNA bacteriophages is controlled by phage-encoded small integral membrane proteins, holins. Holins are the gatekeepers of the lysis process, possessing an intriguing ability to be triggered, at a precise time point, to form large holes in the cytoplasmic membrane of phage-infected bacteria. The paper by Savva et al. in this issue of Molecular Microbiology invites us to take a closer look at this membrane lesion. For the first time, a structural characterization of large-diameter rings formed by these peculiar membrane proteins is presented.