Comparative Analysis on Large Hydrophobic Residues and Small Hydrophobic Residues in Different Organisms

Abstract

One of the major tasks carried by biologist today is to understand the nature of proteins. How this large protein molecule folds themselves into some form and carryout the prescribed biochemical reactions. Hydrophobic interaction is the dominant force towards this task. To understand this interaction, a simple statistical analysis on the contribution of hydrophobic residues was carried out. Large Hydrophobic Residues (LHR) such as Phenylalanine (F), Isoleucine (I), Leucine (L), Methionine (M) and Valine (V) -(FILMV) as well as small hydrophobic residues (SHR) Glycine (G), Alanine (A), Proline (P), Cysteine (C) and Tryptophan (W) -(GAPCW) were studied in all proteins of given organisms. The organisms include Homo sapiens, Macaca Mullatta, Pan troglodytes, Canis familiaris, Gallus gallus, Mus musculus, Rattus norvegicus, Bos taurus, Drosophila melonogaster, Monodelphis domestica, Danio rerio, Stronglycentrolus purpuratus, Anopheles gambiae, Apis mellifera, Arabidopsis thaliana, Tribolium castaneum, Saccharomyces cerevisae, Schizosaccharomyces pombe and Caenorhabditis elegans. It is observed that the protein prefers to have 27% large hydrophobic residues to maintain the required hydrophobicity. In animal, particularly in human, it is observed less. It is interesting to note that small hydrophobic residues balance this lack in number by a factor of 1:3. So is the reason why the length of the animal proteins increases. This new finding on the contribution of hydrophobic residues in protein stability will be discussed in detail.