Study on Different types of Structure based Properties in Human Membrane Proteins

Abstract

Understanding the structure and function of membrane proteins will be useful for applications in industrial protein engineering. Amino acid residues along the primary sequence interact with each other in a cooperative manner to form the stable native structure, during the process of protein folding. To understand the mechanism of protein folding and stability, the knowledge about inter-residue interactions in protein structures is very helpful. In this comparative study, we have systematically analyzed aminoacid composition and various structure based properties of molecular interactions in different classes of human membrane proteins. Parameters used in the study are aminoacid composition, long range order, surrounding hydrophobicity, long range interactions, medium range interactions, accessible surface area, ionic interactions and hydrophobic interactions. Structural based properties of different types of human membrane proteins were statistically analyzed. The results obtained in this work highlight the difference in different structure based properties like long range order, surrounding hydrophobicity, long range interaction ratio, and medium range interaction ratio, average number of residues within 8A and accessible surface area of proteins, in different types of human membrane proteins. Ionic interacting residues have higher value of surrounding hydrophobicity and higher value of neighbors within 8A, compared to ionic noninteracting residues. Accessible surface area of polar residue was found to be greater than nonpolar residues. There is marked difference in structural based properties of buried and non buried residues. Buried residues have higher value of surrounding hydrophobicity and higher value of neighbors within 8A, compared to non-buried residues. Hydrophobic interacting residues have higher value of surrounding hydrophobicity and higher value of neighbors within 8A, compared to hydrophobic noninteracting residues. Long range interactions are more prominent in hydrophobic interactions than in ionic interactions.