Proteins that help bacteria resist antibiotics identified

February 26th, 2008 - 1:43 pm ICT by admin  


Washington, Feb 26 (ANI): Scientists at Ohio State University have identified two proteins that help disease-causing bacteria cells put up a fight and resist certain antibiotics.

They studied two distinct forms of proteins called multiple peptide resistance factors (MprFs), MprFs 1 and MprFs 2.

The findings revealed that these proteins played a vital role in allowing the bacteria cells to change the electrical charge of their membrane and develop their resistance to certain antimicrobial agents.

Both of these proteins are potentially very good drug targets because in theory, if you can target them and inhibit their action, you can make bacteria strains more susceptible to existing antibiotics, said Michael Ibba, associate professor of microbiology at Ohio State and a co-author of the study.

Antibiotics carry a positive charge that attracts them to negatively charged bacteria cells. The opposite charges allow antibiotics to penetrate and kill bacteria.

But if the naturally occurring negative charge is changed to positive, bacteria cells establish a protective coat that ward off the antibiotic.

Lead researchers Ibba and Herve Roy of Ohio State investigated the activities of these specific MprF proteins, from the pathogen Clostridium perfringens, one of the most common sources of food poisoning in the United States.

According to the researchers, MprF proteins affect the membranes charge by using an adapter molecule, called transfer RNA (tRNA), to transfer amino acids to the lipids that make up the cell membrane, which also change in its charge.

The findings revealed that both the proteins performed same function but used different amino acids. MprF2 used amino acid lysine while MprF1 used the amino acid alanine.

This is a new function that we discovered, that MprF1 uses alanine, which then allows the cell to fine tune the properties of the membrane, said Roy.

Earlier studies found these effects on the membrane, but no one knew what protein caused it, he added.

The findings appear online in this weeks issue of Proceedings of the National Academy of Sciences. (ANI)

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