Bacteria draw from an arsenal of weapons to combat the drugs intended to kill them. Among the most prevalent of these weapons are ribosome-modifying enzymes. These enzymes are growing increasingly common, appearing worldwide in clinical samples in a range of drug-resistant bacteria.
Now scientists have captured the first images of one important class of these enzymes in action. The images show how the enzymes latch onto a particular site on the bacterial ribosome and squeeze it like a pair of tweezers to extract an RNA nucleotide and alter it. The Proceedings of the National Academy of Sciences (PNAS) published the findings, led by scientists at Emory University.
The advanced technique of cryoelectron microscopy made the ultra-high-resolution, three-dimensional snapshots possible.
“Seeing is believing,” says Christine Dunham, Emory professor of chemistry and co-corresponding author of the paper. “The minute you see biological structures interacting in real life at the atomic level it’s like solving a jigsaw puzzle. You see how everything fits together and you get a clearer idea of how things work.”
The insights may lead to the design of new antibiotic therapies to inhibit the drug-resistance activities of RNA methyltransferase enzymes. These enzymes transfer a small hydrocarbon known as a methyl group from one molecule to another, a process known as methylation.
“Methylation is one of the smallest chemical modifications in biology,” says Graeme Conn,