A novel super‐secondary structure of proteins and the relation between the structure and the amino acid sequence

A novel protein super‐secondary structure which is referred to as an αα‐corner is considered. The αα‐corner is formed by two consecutive α‐helices packed approximately crosswise and connected by two or more peptide units. It is shown that the amino acid sequences coding for the αα‐corners have a strictly definite order of hydrophobic, hydrophilic and glycine residues. A hypothesis is suggested that the αα‐corner can be an embryo of protein folding.