Scientists identify proteins that help bacteria put up a fight

Link: Scientists identify proteins that help bacteria put up a fight.

Scientists have already observed that the cell membranes of many disease-causing bacteria develop resistance by changing their electrical charge from negative to positive. Many antibiotics work because they carry a positive charge that attracts them to negatively charged bacteria cells. The opposite charges allow antibiotics to penetrate and kill bacteria. But by changing their naturally occurring negative charge to positive, some bacteria cells establish a protective “coat” that repels the antibiotic. A common example of antibiotic resistance is Methicillin-resistant Staphylococcus aureus (MRSA), the strain of bacteria responsible for thousands of difficult-to-treat infections reported in humans each year. “There is a dispute that remains unresolved as to whether or not this pathway we’re investigating is involved in MRSA. It’s very unclear. By understanding the mechanism, we might be able to find out if this is involved in MRSA or not,” Ibba said. Ibba and Hervé Roy, a postdoctoral researcher at Ohio State and lead author of the study, concentrated on exploring the activities of these specific MprF proteins, which are just two of dozens of forms of a class of genes associated with the development of resistance in about 200 bacteria species. They investigated the activity of two forms of MprF from the pathogen Clostridium perfringens, one of the most common sources of food poisoning in the United States. MprF proteins affect the membrane’s charge by using an adapter molecule, called transfer RNA (tRNA), to transfer amino acids to the lipids that make up the cell membrane. This action leads to modification of the membrane and the change in its charge.