COLUMBUS, Ohio Salmonella cells have hijacked the protein-building process to maintain their ability to cause illness, new research suggests.
Scientists say that these bacteria have modified what has long been considered typical cell behavior by using a beta form of an amino acid as opposed to an alpha form during the act of making proteins.
Beta versions of amino acids occur in nature under rare and specific circumstances, but have never been observed as part of protein synthesis. Before this finding, in fact, researchers had determined that virtually all proteins were constructed with the alpha forms of amino acids.
This work has shown that when researchers delete any one of three genes from the process that makes use of the beta form of the amino acid, or if they insert the alpha form in the beta version's place, Salmonella cells are no longer able to cause disease. The amino acid in question is lysine, one of 22 genetically encoded amino acids that are strung together in cells to make proteins.
"When these genes were knocked out, the cells became sensitive to antibiotics. And if we put beta lysine into the medium where cells were growing, they became resistant to antibiotics," said Michael Ibba, professor of microbiology at Ohio State University and a senior author of the study. "So we could see the beta amino acid being taken up and used. The cells really do need the beta amino acid to be resistant to antibiotics, and for other aspects of their virulence."
This finding suggests that the process using this specific beta amino acid could be an attractive antibiotic target for this common pathogen, the researchers say.
The Centers for Disease Control and Prevention estimates that about 1.4 million people in the United States are infected with Salmonella each year, though only 40,000 cases are reported. Most people infected with Salmonella develop diarrhea, fever and abdomi
|Contact: Michael Ibba|
Ohio State University