Abstract
Protein standard structures formed by two consecutive β‐strands connected by short loops are considered in this paper. A stereochemical analysis of each standard structure has been performed to determine the necessary conditions which must be fulfilled in the amino acid sequence encoding the standard structure. It is shown that amino acid sequences coding for the same standard structure in ditterent proteins have practically the same order of hydrophobic, hydrophilic and glycine residues. The results of the stereochemical analysis are confirmed by a large number of examples from known protein structures.