X-ray laser films bacteria-induced antibiotic inactivation
November 2021
University of Wisconsin-Milwaukee, Milwaukee, USA
The progressive occurrence of antibiotic resistance increasingly complicates the treatment of bacterial diseases. In the present study, the catalytic inactivation of the cephalosporin antibiotic ceftriaxone by the enzyme beta-lactamase of tuberculosis pathogens was investigated. A newly developed mix-and-inject technique in combination with a high-resolution X-ray Free-Electron Laser (XFEL) now enables atomically accurate slow-motion images of enzyme-substrate reactions and provides new insights into the spatial structure, arrangement and connection of biomolecules. For biomedical analysis, the enzyme molecules to be investigated were arranged three-dimensionally in synthesized micro-crystals, through which the researchers had the antibiotic (AB) diffused through in a controlled manner. The crystals were then irradiated with the XFEL at the exactly calculated time of the enzyme-substrate reaction. The results showed that the AB docked to two binding tables of the beta-lactamase within a few milliseconds and was inactivated. The research group conducted another series of experiments in which they diffused the enzyme inhibitor sulbactam through the crystals. It was found that the inhibitor occupied all four binding sites of the beta-lactamase and that already formed AB resistances could be deactivated again. In the future, the researchers would like to generate further "snapshots" in order to be able to understand the entire process. For the first time, the method enables a real-time view of the active centres of an enzyme during substrate binding and thus could be a valuable tool for future biomedical research.
Observation of substrate diffusion and ligand binding in enzyme crystals using high-repetition-rate mix-and-inject serial crystallography
Marius Schmidt
Added on: 08-07-2022
[1] https://journals.iucr.org/m/issues/2021/06/00/mf5055/index.html[2] https://www.bionity.com/en/news/1172932/filming-antibiotic-resistance-in-slow-motion.html
