( Frog skin and human lungs hold secrets ...)Natural antibiotics yield secrets to atom-level imaging technique

That's the view of University of Michigan researcher Ayyalusamy Ramamoorthy, who will discuss his group's progress toward that goal March 3 at the annual meeting of the Biophysical Society in Baltimore, Md.

Ramamoorthy's research group is using solid-state NMR to explore the germ-killing properties of natural antibiotics called antimicrobial peptides (AMPs), which are produced by virtually all animals, from insects to frogs to humans. AMPs are the immune system's early line of defense, battling microbes at the first places they try to penetrate: skin, mucous membranes and other surfaces. They're copiously produced in injured or infected frog skin, for instance, and the linings of the human respiratory and gastrointestinal tracts also crank out the short proteins in response to invading pathogens.

In addition to fighting bacteria, AMPs attack viruses, fungi and even cancer cells, so drugs designed to mimic them could have widespread medical applications, said Ramamoorthy, who is an associate professor of chemistry and an associate research scientist in the Biophysics Research Division.

While researchers have identified hundreds of AMPs in recent years, they're still puzzling over exactly how the peptides wipe out bacteria and other microbes. Unlike conventional antibiotics, which typically inhibit specific bacterial proteins, AMPs get downright physical with invaders, punching holes into their membranes. But they're selectively pugnacious, targeting microbes but leaving healthy host cells alone.

"They're like smart bombs," Ramamoorthy said. "We'd like to exploit their properties to design super-smart bombs, but before we can do that, we need to understand how these AMP smart bombs interact with membranes to destroy bacteria. We need to know how they're shaped befo
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Source:University of Michigan