Coiled-coils in alpha-helix-containing proteins: analysis of the residue types within the heptad repeat and the use of these data in the prediction of coiled-coils in other proteins.

Portions of the amino acid sequences of four representative proteins containing alpha-helices arranged in a coiled-coil rope-like structure have been analysed in terms of the preference of the residues or residue types for specific positions within the observed heptad repeats. The results clearly show an asymmetric distribution of residues which can be interpreted in terms of the size and shape of the residue, the geometry of the coiled-coil structure, or the facility with which interchain or intermolecular interactions may be made. The statistical data reported here may also be used to predict regions of coiled-coil structure in other proteins.