On the relationship between sequence and structure similarities in proteomics

Statistical analysis of multiple and pairwise structural alignments of protein structures within SCOP folds is performed. The results indicate that multiple conservation of residue identity is not common and that relationship between sequence and structure may be explained by a model based on the assumption that protein structure is tolerant to residue substitutions preserving hydropathic profile of the sequence. This model also explains the origin and specific value of the sequence similarity threshold, noticed in many previous studies, below which structural resemblance is not statistically expected.