First 3D view of a key protein from the SARS virus

27 July 2006

Researchers at Oxford University have ‘seen’ in detail the three-dimensional molecular structure of a protein from the SARS (severe acute respiratory syndrome) virus. The work, published in the journal Structure, represents a significant advance in understanding the molecular basis of the life-threatening SARS disease.

Led by Professor David Stuart at Oxford’s Wellcome Trust Centre for Human Genetics, the team determined the structure of a SARS protein called ORF-9b. By aiming X-rays through a crystallized form of the protein, a three-dimensional image – precise down to the atom – was obtained.

This high-resolution image reveals that the core of the ORF-9b protein contains a tunnel which can interact with lipid molecules (molecules containing fatty acids). This unexpected finding is important because the SARS virus manages to surround itself with lipids derived from the human body.‘The structure gives us a first glimpse of how the virus might be holding on to its lipid envelope,’ says Christoph Meier, a Wellcome Trust graduate student in Professor Stuart’s lab and lead author of the study.

Another surprise emerged when the Oxford researchers compared the structure of ORF-9b to that of other proteins: ‘On a molecular level, many proteins are similar to one another because they are related through evolution,’ says Meier. ‘But the ORF-9b protein is different – our analysis reveals that the protein is not related to any known structure. This suggests that evolution threw up ORF-9b very recently. This is exciting, because the evolution of SARS – the question how this dangerous virus arose – is a great mystery. Our research may help solve it.’

For the full research paper, go to the Structure website: http://www.structure.org/content/current