The molecular structure of a key avian influenza protein reveals a quirk that could be used to design more potent drugs against pandemic flu, report John Skehel and his colleagues in a paper to be published online by Nature (Vol. 442, No. 7104, 17 August 2006).
The H5N1 virus that is spreading around the globe gets its initials from the haemagglutinin (H) and neuraminidase (N) proteins on the coat of the virus, and each protein comes in several different forms. The neuraminidase helps the virus to escape infected cells and attack new ones, and is targeted by the drugs oseltamivir (Tamiflu) and zanamivir (Relenza). But these drugs were designed on the basis of the crystal structures for neuraminidases N2 and N9 - the only structures available until now.
The structure of the N1 enzyme - and closely related N4 and N8 enzymes - exposes a key difference in enzyme configuration when compared with the previous structures: a cavity in one corner of the active site that closes when it locks onto its target proteins. This difference could potentially be exploited to design much-needed drugs that bind more snugly into this active site, and perhaps sidestep the drug resistance that some viruses have already acquired to Tamiflu.
John Skehel (National Institute of Medical Research, London, UK)
Ming Luo (University of Alabama, Birmingham, AL, USA)
(C) Nature press release.
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