Protein changes on virus change strain

The influenza virus continually undergoes slight modifications to the proteins covering its surface, causing the new strains, a Canadian researcher says. Chemistry Professor Andrew Bennet of the Simon Fraser University in Vancouver, British Columbia, said such small changes mean that every year a slightly different strain of influenza circulates through the human population, requiring a new vaccine. In addition, the virus will swap one of its surface proteins with that from a bird-infective influenza strain -- the H5N1 bird flu, for example -- which has over the past century resulted in three major pandemics. H5N1 strains are currently not effectively transmitted between humans. Inhibition of one of the viral surface proteins called neuraminidase -- the 'N' in H5N1 -- which catalyzes the release of newly formed virus particles from the infected cells, has proven to be a suitable approach in the design of anti-viral drugs. Bennet and researchers are working to learn more about how the influenza enzyme works, by using imaging technology similar to magnetic resonance imaging to "tag" atoms in a sugar molecule that the virus removes during its replication cycle. "Scanning the atoms within this sugar molecule provides the necessary information to guide the design of drug candidate molecules," Bennet said in a statement. Bennet discussed the research on Cafe Scientifique on the CBC.