Nature Structural & Molecular Biology pp 963-967

Many antibiotics kill bacteria by weakening their cell walls. However, some bacteria are finding ways to prevent the destructive action of the antibiotics, and drug-resistant pathogens have become an increasingly critical public health issue. Nisin is one promising antibiotic in the battle against drug-resistant bacteria. A report in the October issue of Nature Structural & Molecular Biology reveals how nisin binds to a portion of lipid II, an essential component of the cell wall. Understanding this interaction could facilitate the design of new antibiotics.

Nisin is a naturally occurring antibiotic and a commonly used food preservative. It is a promising candidate for antibiotic therapy because it is active at lower concentrations than other naturally occurring antibiotics and is not toxic to humans. Kaptein and colleagues (Utrecht University, The Netherlands) report the solution structure of the complex of nisin bound to a variant of lipid II. The structure reveals that the antibiotic forms a cage-like structure enclosing the cell wall component. The authors suggest that this structure may lead to the formation of a nisin pore on the cell surface, thereby explaining its activity.

Overprescription of antibiotics has contributed to an emergence of drug-resistant bacteria and the need to develop novel antibiotic agents has become urgent. About 70 percent of bacteria that cause hospital infections are resistant to at least one of the drugs most commonly used to treat infections. Some bacteria are resistant to all approved antibiotics. The structure described by Kaptein and colleagues may provide the template for the design of novel or improved antibiotics.