GARY, Ind. A group of proteins that act as the body's built-in line of defense against invading bacteria use a molecular trick to induce bacteria to destroy themselves, researchers at the Indiana University School of Medicine have determined. The research could point the way toward new anti-bacterial treatments that could take on bacteria that are resistant to antibiotics.
The proteins, called Peptidoglycan Recognition Proteins (PGRPs), are able to detect and target bacteria because bacteria are unique in having peptidoglycan polymers in their cellular walls. However, the mechanism by which PGRPs are able to kill bacteria had not been determined.
A research team led by Roman Dziarski, Ph.D., professor of microbiology and immunology at Indiana University School of Medicine Northwest, reported May 22 in the advance online edition of the journal Nature Medicine that the PGRPs are able to induce a suicide response in the targeted bacteria.
The PGRPs accomplish the mission by binding to specific sites in bacterial cell walls in ways that exploit a bacterial defense mechanism known as protein-sensing two-component systems. These systems, which normally enable the bacteria to detect and eject malformed proteins, interpret the PGRPs as just such malformed proteins. Unable to dislodge the PGRPs, the bacteria then activate a suicide response, the researchers said.
This approach is different than those employed by other anti-bacterial mechanisms, such as the immune system's white blood cells, said Dziarski.
"This could be a target to develop new anti-bacterial applications," Dziarski said.
Dziarski and colleague Dipika Gupta, Ph.D., associate professor of biochemistry and molecular biology at Indiana University School of Medicine Northwest, first cloned the PGRP genes in 2001. The PGRP genes, which are found in species ranging from insects to mammals, are part of the body's innate immune system, in contrast
|Contact: Eric Schoch|
Indiana University School of Medicine