The diagram shows the principles of a new method which can be used to detect the possible fold of a protein from a predicted structure. It is being developed by Robert Russell from the Imperial Cancer Research Fund Laboratories in Lincoln's Inn Fields, London with Richard Copley and Geoff Barton from the Laboratory of Molecular Biophysics at the University of Oxford. The order and length of helices and strands in a query (ras p21) are compared with the order of these structures in a database of known three dimensional folds. An initial set of matched protein fragments are subjected to further tests before the computer program recognises a similarity to the "TU elongation factor" protein.