Before the new study, "it wasn't clear how a peptidase could destroy an antibiotic," Nair said.
To get a fuller picture of the structure of the peptidase, Illinois graduate student Vinayak Agarwal crystallized MccF while it was bound to other molecules, including the antibiotic. An analysis of the structure and its interaction with the antibiotic revealed that MccF looked a lot like other enzymes in its family, but with a twist or, rather, a loop. Somehow MccF has picked up an additional loop of amino acids that it uses to recognize the antibiotic, rendering it ineffective.
"Now we know that specific amino acid residues in this loop are responsible for making this from a normal housekeeping gene into something that's capable of degrading this class of antibiotics," Nair said.
With this information, researchers and eventually, doctors and other clinicians will be able to scan the genomes of disease-causing bacteria to find out which ones have genes with the antibiotic-resistance loop in them, Nair said. "If we know what type of bacteria are causing an infection we know what kind of antibiotic to give and what kind not to give," he said.
Nair is also an affiliate of the Center for Biophysics and Computational Biology, the department of chemistry and of the Institute for Genomic Biology at Illinois. The research team included scientists from the Russian Academy of Sciences and Rutgers University.
|Contact: Diana Yates|
University of Illinois at Urbana-Champaign