  While all the information required for the folding of a protein is contained
in its amino acid sequence, one has not yet learnt how to extract this
information so as to predict the detailed, biological active, three-dimensional
structure of a protein whose sequence is known. This situation is not
particularly satisfactory, in keeping with the fact that while linear
sequencing of the amino acids specifying a protein is relatively simple to
carry out, the determination of the folded-native-conformation can only be done
by an elaborate X-ray diffraction analysis performed on crystals of the protein
or, if the protein is very small, by nuclear magnetic resonance techniques.
Using insight obtained from lattice model simulations of the folding of small
proteins (fewer than 100 residues), in particular of the fact that this
phenomenon is essentially controlled by conserved contacts among strongly
interacting amino acids, which also stabilize local elementary structures
formed early in the folding process and leading to the (post-critical) folding
core when they assemble together, we have worked out a successful strategy for
reading the three-dimensional structure of a notional protein from its amino
acid sequence.
