A group of researchers from the University of Illinois, including an Indian, solved a 25-year-old mystery on how Nisin, a powerful antibiotic agent is made in nature.
Nisin is a natural product in milk that can be synthesised in the lab and used as a preservative in food and its properties undergo several modifications in the cell after it is made, taking its final form and function. The current research helped scientists to understand how these changes occur ending the decades-old mystery with huge potential in future study.
“Peptides (including Nisin) are a little bit like spaghetti; they are too flexible to do their jobs,” said, University of Illinois chemistry professor, Wilfred van der Donk, who led the research along with Indian-origin biochemistry professor Satish K. Nair. “So what nature does is, it starts putting knobs in, or starts making the peptide cyclical,” van der Donk added.
Special enzymes help in the task. For nisin, an enzyme called a dehydratase removes water to help give the antibiotic its final, three-dimensional shape. This is the first step in converting the spaghetti-like peptide into a five-ringed structure, the researchers noted.
The rings are essential to nisin’s antibiotic function: Two of them disrupt the construction of bacterial cell walls, while the other three punch holes in bacterial membranes. This dual action is very effective, making it difficult for microbes to evolve resistance to the antibiotic, the findings showed.
“It turns out that in nature, a fairly large number of natural products – many of them with therapeutic potential – are made in a similar fashion,” van der Donk concluded.
This finding has opened up new avenues of research into thousands of similar molecules, many of which are likely to be medically useful. The study was published in the journal Nature.