Computational analysis of hydrophobicity across six enzyme classes revealing relative contribution of aliphatic and aromatic residues

One of the fundamental contributing factors, essential in folding of a linear chain of amino acids into a three dimensional protein structure is hydrophobicity and this information for protein to fold into specific geometry lies with the primary sequence itself. Thus, mapping of the hydrophobic amino acids in a protein molecule often provide ideas about the folding patterns, secondary structural arrangements, tertiary properties etc., all of which lead to functional attainment of the molecule. The present investigation intends to determine the hydrophobic constituents in various classes of enzymes obtained from different organisms. The analysis has revealed a notable point of similarity in the percentage distribution of aromatic and aliphatic hydrophobic amino acids among the different enzyme classes. The common distribution pattern of hydrophobic percentage of amino acids across the enzyme classes possibly argue in favour of a structural need, might be for folding of the peptide chains of the enzymes, even when enzyme classes are meant for diverse functions. Phenylalanine and Leucine contribute the most to aromatic and aliphatic hydrophobic content respectively across the six classes; interestingly, both happen to be at the second position in hydrophobic scale of their categories. Understanding of the hydrophobic distribution in detail seems to offer certain basic tenets and better success of protein engineering experiments.