[Architecture of compact three alpha-helical structures].

Modeling and methodical analysis of possible compact spatial arrangements of three alpha helices bound with connections were carried out. It was suggested to describe the compact three-alpha-helical structures as combinations of alpha-helical hairpins, L-shaped structures, V-shaped structures, alpha-alpha comers, and alpha-l-alpha motifs. Practically all the structures resulting from such a modeling were shown to exist in globular proteins. Many small proteins and domains were found to consist of only these three-helical structures. This indicated that each such three-helical structure was stable by itself and capable of independent folding of its polypeptide chain into this structure.