Spectroscopic, structural and thermodynamic properties of chlorpyrifos bound to serum albumin: A comparative study between BSA and HSA.
Chlorpyrifos (CPF) is a widely used organophosphate insecticide which could bind with human serum albumin (HSA) and bovine serum albumin (BSA). The binding behavior was studied employing fluorescence, three-dimensional fluorescence, Circular dichroism (CD) spectroscopy, UV-vis absorption spectroscopy, electrochemistry and molecular modeling methods. The fluorescence spectra revealed that CPF causes the quenching of the fluorescence emission of serum albumin. Stern-Volmer plots were made and quenching constants were thus obtained. The results suggested the formation of the complexes of CPF with serum albumins, which were in good agreement with the results from electrochemical experiments. Association constants at 25°C were 3.039 × 10(5) mol L(-1) for HSA, and 0.3307 × 10(5) mol L(-1) for BSA, which could affect the distribution, metabolism, and excretion of pesticide. The alterations of protein secondary structure in the presence of CPF were confirmed by the evidences from UV and CD spectra. Site competitive experiments also suggested that the primary binding site for CPF on serum albumin is close to tryptophan residues 214 of HSA and 212 of BSA, which was further confirmed by molecular modeling.
State Key Laboratory of Virology (Ministry of Education), College of Chemistry and Molecule Sciences, Wuhan University, Wuhan 430072, PR China.
Xiao-Le
XL
Han
Fang-Fang
FF
Tian
Yu-Shu
YS
Ge
Feng-Lei
FL
Jiang
Lu
L
Lai
Dong-Wei
DW
Li
Qiu-Liyang
QL
Yu
Jia
J
Wang
Chen
C
Lin
Yi
Y
Liu
D000818:Animals; D002417:Cattle; D004390:Chlorpyrifos / Q000737:chemistry* / Q000378:metabolism*; D004563:Electrochemistry; D006801:Humans; D007306:Insecticides / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013057:Spectrum Analysis; D013816:Thermodynamics
D007306:Insecticides; D012710:Serum Albumin, Bovine; D004390:Chlorpyrifos