Fluorescence study on the interaction of bovine serum albumin with p-aminoazobenzene.
In this paper, the interaction between p-aminoazobenzene (PAAB) and BSA was investigated mainly by fluorescence quenching spectra, circular dichroism (CD) and three-dimensional fluorescence spectra under simulative physiological conditions. It was proved that the fluorescence quenching of BSA by PAAB was mainly a result of the formation of a PAAB-BSA complex. The modified Stern-Volmer quenching constant K(a) and the corresponding thermodynamic parameters DeltaH, DeltaG and DeltaS at different temperatures were calculated. The results indicated that van der Waals interactions and hydrogen bonds were the predominant intermolecular forces in stabilizing the complex. The distance r=4.33 nm between the donor (BSA) and acceptor (PAAB) was obtained according to Förster's non-radioactive energy transfer theory. The synchronous fluorescence, CD and three-dimensional fluorescence spectral results showed that the hydrophobicity of amino acid residues increased and the losing of alpha-helix content (from 63.57 to 51.83%) in the presence of PAAB. These revealed that the microenvironment and conformation of BSA were changed in the binding reaction.
Zhang
Ye-Zhong
YZ
Department of Chemistry, College of Chemistry and Environmental Engineering, Yangtze University, JingZhou, Hubei 434025, People's Republic of China.
Zhou
Bo
B
Liu
Yan-Xia
YX
Zhou
Chun-Xia
CX
Ding
Xin-Liang
XL
Liu
Yi
Y
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D005453:Fluorescence; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014364:Tryptophan; D010128:p-Aminoazobenzene / Q000378:metabolism*
D012710:Serum Albumin, Bovine; D010128:p-Aminoazobenzene; D014364:Tryptophan