Scientists visualise cellular handmaiden that restores shape t...( ticians searching for similar molecule...)

The team believe their structure leads them to an explanation of how the molecule works.

Properly folded proteins tuck away the elements that don't mingle well with water - a property known as hydrophobicity - inside their structure. Denatured proteins with their mis-organised shape allow normally hidden elements to display on the outside, making them appear hydrophobic.

The chaperonin cap recognises the hydrophobicity and 'kicks' the out of shape protein in to the cage for some protein folding therapy.

The folding changes in the cavity are driven by the cell's energy source, ATP. It takes just 10 seconds for a protein to properly fold in the cavity.

The scientists' next goal is to capture these cellular handmaidens in the act of folding strings of denatured protein back together again.

They already have clues as to the sorts of proteins that might be fixed by the chaperonin complex - during their work to crystallise the protein structure they identified 28 separate proteins inside the cage.

"We'd like to be the first to really know what happens, when the protein is enclosed and caught in the act," says Professor Iwata.

In molecular units known as Daltons, the structure of the native chaperonin complex weighs 700 kiloDaltons. It is so big that details of its full structure had to be deposited in two parts to the freely available structure database, Protein Data Bank. It has more than six digits of atomic coordinates, or over a million atoms in the structure mapped and plotted in 3D space.

Professor Iwata is well known for solving the structure of proteins embedded in the membrane of cells, such as the crucial photosynthesis enzyme Photosystem II, published last year in Sc
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17-Aug-2004