Fluorescence spectroscopic analysis of heavy metal induced protein denaturation

Abstract

Protein denaturation occurs when the secondary and tertiary structures of protein undergo conformational changes and native state of protein is destroyed. The most common observation of the denaturation phenomenon is either coagulation or precipitation of proteins. Since the denaturation processes are not strong enough to break the peptide bonds, the amino acid sequence is not perturbed and hence the primary structure of proteins is not affected and uncoils itself into a random shape. There are variety of reagents and conditions which can protein denaturation, such as urea, temperature, pH, alcohol, heavy metal, etc. Heavy metal salts present in the vicinity of a protein can induce protein denaturation by disturbing the disulfide bond. Heavy metal salts which induce protein denaturation are usually Hg2+, Pb2+, Ag+,Tl+, Cd2+and other metal ions with high atomic weights. The heavy metal salts usually reacts with a protein forming insoluble metal-protein salt. Salts such as silver nitrate are used to prevent gonorrhea infections in the eyes of new born infants. It is also used in treatment of various infection and wounds.The current work will involve the fluorescence spectroscopic studies on protein denaturation induced by heavy metal salts; as reported by the fluorescence probing technique. For this study, we will use bovine serum albumin (BSA) is chosen as the protein. The fluorescent property of Tryptophan (Trp) moiety of BSA can be utilized for the study. It can be understood that in present of silver salt, there is Trp fluorescence quenching and data reveals the denaturation of BSA.