The invention provides methods and apparatus for analyzing a protein structure by A) receiving a reference structure (A) forming a three dimensional representation of a protein; B) substituting into the structure of (A) a pattern with amino-acids different from the one of the protein; C) optimizing the conformation of (A) substituted by pattern of (B); D) assessing the energetic compatibility (EC) of the pattern of (B) within the context of the structure of (A) being structurally optimized in (C) with respect to the pattern, by comparing the global energy of the substituted and optimized protein structure with the global energy of the non-substituted reference structure; and E) storing a value reflecting the EC of the pattern together with information related to the structure of the pattern in the form of an energetic compatibility object (ECO).