April 27, 2009

Infection study may lead to new drugs

U.S. government scientists say they have decoded the structure of a protein complex secretion system that is essential for infection.

The research, conducted in part at the U.S. Department of Energy's Brookhaven National Laboratory, involving a needle-like protein complex on the surface of certain bacteria may help scientists develop new strategies to thwart infection.

The scientists said their research involved a needle-like protein complex known as a type III secretion system, on the surface of Shigella bacteria, a cause of dysentery. The secretion system is a complex protein structure that traverses the bacterial cell membrane and acts as a biological syringe to inject deadly proteins into intestinal cells. Those proteins rupture the cell's innards, leading to bloody diarrhea and sometimes death. The researchers said, noting similar secretion systems exist in a range of other infectious bacteria.

Understanding the 3D structure of these secretion proteins is important for the design of new broad-spectrum strategies to combat bacterial infections, said study co-author Joseph Wall, a biophysicist at Brookhaven Lab.

The study is detailed in the advanced online edition of the journal Nature Structural & Molecular Biology.