Bald bacteria can't get a grip.

Scientists have devised a way to make bacteria go bald, losing their "hair" and with it their ability to adhere to throats, nasal passages, kidneys, and other tissues. The idea is to use a newly designed peptide to collapse the scaffolding bacteria use to assemble pili--thousands of hair-like projections with sticky tips that enable bacteria to gain a stronghold in the human body. Without the scaffolding, bacteria are unable to construct adhesive pili and are washed off tissues by body fluids, explains Scott J. Hultgren, assistant professor of molecular microbiology, Washington University School of Medicine.

Hultgren's research team produced the first molecular snapshots of the bacterium E. coli in the process of assembling the machinery it uses to build its adhesive projections. More importantly, the pictures showed that a peptide designed by the researchers interferes with this construction process and grinds it to a halt.

Pili, it turns out, are much more complicated than they seem. They do not stick to tissues randomly and are extremely finicky about where they will attach. Pili constantly are on the lookout for a specific receptor that they can fit into with "lock and key specificity," Hultgren indicates. This is one of the main reasons that bacteria latch onto specific tissues. Uropathogenic E. coli, for instance, prefers the bladder, urinary tract, and kidney because those tissues contain receptor "locks" that fit the E. coli pilus' "keys."

One of the main features in E. coli synthesis is a boomerang-shaped protein called papD--a member of a family of proteins known as chaperones because their job is to supervise and oversee the assembly of pili. Periplasmic chaperones make sure proteins don't engage in "nonproductive interactions" in the...