Norovirus enzyme crystallised

The successful crystallisation of a key norovirus enzyme could enable scientists to develop effective treatments for the winter vomiting bugs

Southampton norovirus with a possible therapeutic drug preventing it from working Credit: University of Southampton

Scientists from the University of Southampton were able to crystallise a key protease enzyme in the Southampton norovirus – so-called because this particular virus was first isolated in a family in Southampton.

Crystallising the enzyme allowed researchers to predict what shape molecule will fit into the enzyme’s active site and design an inhibitor that interacts with the enzyme and prevents it from working.

The chemically synthesised inhibitor mimics the natural substrate of the enzyme and fits exactly in the enzyme’s active site. Once bound, the inhibitor cannot be released as would normally happen, and stops the critical protease enzyme in the norovirus from working. The enzyme is prohibited from cutting more its natural substrate and the virus is unable to spread.

“Noroviruses place a huge burden on the NHS. This is an important step in the rational design of new drugs to treat norovirus infections,” said virologist Professor Ian Clarke. “We know the drug works in the test tube, the next step is to see whether we can modify and deliver it to the site where the virus grows.”

There are an estimated one million cases of norovirus per year in the UK, causing acute diarrhoea and vomiting. It can spread rapidly from person to person.

Each virus is named after the place it was first found, in this case Southampton. The very first norovirus was discovered in November 1968 after an outbreak of acute gastroenteritis in an elementary school in Norwalk, Ohio.