Defensins' offensive play: exploiting a viral achilles' heel.

Vertebrates rely on antimicrobial peptides as a front-line defense against invading pathogens. Certain cationic antimicrobial peptides, such as human alpha-defensins, have traditionally been thought to destroy invading microbes by disrupting their lipid membranes. In this issue of Cell Host & Microbe, Smith and Nemerow reveal that alpha-defensins can inactivate adenoviruses, which lack lipid membranes, through direct binding of the defensin to the virus's naked protein shell.