Left‐handed topology of super‐secondary structure formed by aligned α‐helix and β‐hairpin

A novel super-secondary structure common for many non-homological proteins is considered. This folding pattern, consisting of adjacent along the chain alpha-helix and beta-hairpin, has an aligned packing. It is found that one of the two possible 'mirror-symmetrical' topologies is observed in proteins. The alpha-helix + beta-hairpin structures have a similar pattern of hydrophobic residues in their amino acid sequences. The remaining part of a molecule or a domain is almost always located on the same side of the considered folding pattern. These results can be used in the prediction of three-dimensional protein structure and protein design.