Study on the Secondary Structure of Protein in Solution Containing Pb~(2+) and Bovine Serum Albumin

The interaction between Pb2+ and bovine serum albumin(BSA) has been studied by using ultra-visible spectrum,Fourier transform infrared(FT-IR) spectrum and circular dichroism(CD) spectrum.Results from UV-Vis spectra indicated that Pb2+reacted with CO group of peptide chains of BSA and resulted in the change of micro-environment of Trp and Tyr residues lyophobic.The spectra and data of FT-IR indicated that Pb2+ could interact with —OH and —NH groups.The secondary structure contents of BSA,including α-helix,β-sheet,β-turn and random coil were calculated based on the analysis of amide Ⅰ band of FT-IR by second derivative,Fourier self-deconvolution(FSD) and curve-fitting method.Results showed that the contents of α-helix and β-sheet were decreased while that of β-turn was increased,whereas the content of random coil varied scarcely,which was consistent with the results obtained from CD spectra.Therefore,the reaction between Pb ions and BSA could result in the change of BSA conformation by losing its bio-activity,and finally lead to the pathological change in organism.