Structural entropy to characterize small proteins (70 aa) and their interactions (Q845398)

Summary: Proteins composed of short polypeptide chains (about 70 amino acid residues) participating in ligand-protein and protein-protein (small size) complex creation were analyzed and classified according to the hydrophobicity deficiency/excess distribution as a measure of structural and functional specificity and similarity. The characterization of this group of proteins is the introductory part to the analysis of the so called `Never Born Proteins' (NBPs) in search of protein compounds of biological activity in a pharmacological context. The entropy scale (classification between random and deterministic limits) estimated according to the hydrophobicity irregularity organized in a ranking list allows the comparative analysis of the proteins under consideration. The comparison of the hydrophobicity deficiency/excess appeared to be useful for similarity recognition, examples of which are shown. The influence of mutations on structure and hydrophobicity distributions is discussed in detail.