Researchers from the National Institute for Medical Research in London have discovered a structural element in a key enzyme of the H5N1 avian influenza virus that presents a new avenue for designing anti-influenza drugs (Russell RJ et al. Nature. doi:10.1038/nature05114 [published online ahead of print August 16, 2006]).
The enzyme, neuraminidase, has 9 subtypes, and design of the anti-flu drugs oseltamivir and zanamivir was based on the N2 and N9 forms of the virus. In the current work, the researchers used x-ray crystallography to examine the N1 subtype found in H5N1 avian influenza, as well as 2 other forms (N4 and N8). They found that when N1, N4, or N8 bind their normal target, a small cavity close to the active site opens up.
Stephenson J. Targeting Avian Influenza. JAMA. 2006;296(11):1345. doi:10.1001/jama.296.11.1345-c