Key Laboratory of Pesticide Chemistry and Application Technology

Beijing, China

Key Laboratory of Pesticide Chemistry and Application Technology

Beijing, China
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Ding F.,China Agricultural University | Liu W.,China Agricultural University | Zhang L.,Key Laboratory of Pesticide Chemistry and Application Technology | Yin B.,Key Laboratory of Pesticide Chemistry and Application Technology | Sun Y.,China Agricultural University
Journal of Molecular Structure | Year: 2010

The protein-ligand system constituted by human serum albumin (HSA) and sulfometuron-methyl (SM) has been investigated by using tryptophan fluorescence, UV-vis absorption, circular dichroism (CD) and molecular modeling. The Stern-Volmer analysis indicated that the fluorescence quenching of HSA by SM was resulted from static mechanism, and the binding constants (Kb) were 4.785, 3.803, 3.114 and 2.205 × 104 M-1 at 291, 297, 303 and 309 K, respectively. The secondary structure changes of HSA upon SM binding were evaluated by measuring synchronous fluorescence, UV-vis, far-UV CD and three-dimensional fluorescence spectroscopy properties of the HSA-SM complex. Through site marker competitive experiments, subdomain IIA of HSA has been assigned to possess the high-affinity binding site of SM, and corroborates with the hydrophobic probe ANS displacement results and molecular modeling simulations. In addition, thermodynamic analysis implied the roles of hydrophobic forces, van der Waals forces and hydrogen bonds interactions in stabilizing the HSA-SM complex. The binding research presented in this paper enriches our knowledge of the interaction dynamics of sulfonylurea herbicides to the important plasma protein HSA. © 2010 Elsevier B.V. All rights reserved.


Ding F.,China Agricultural University | Liu W.,China Agricultural University | Li N.,China Agricultural University | Zhang L.,Key Laboratory of Pesticide Chemistry and Application Technology | Sun Y.,China Agricultural University
Journal of Molecular Structure | Year: 2010

Nicosulfuron is a sulfonylurea herbicide developed by DuPont that has been used successfully for weed control in maize. The binding mechanism and binding site identified in human serum albumin (HSA) with the use of fluorescence, circular dichroism (CD) and molecular modeling is the subject of this paper. From the CD, synchronous and three-dimensional fluorescence results, it was apparent that the interaction of nicosulfuron with HSA caused secondary structure changes in the protein. Fluorescence data revealed that the nicosulfuron induced the fluorescence quenching of HSA through a static quenching procedure. Thermodynamic analysis results implied the role of hydrophobic and hydrogen bonds interactions in stabilizing the nicosulfuron-HSA complex. Site marker competitive experiments showed the binding of nicosulfuron to HSA primarily took place in subdomain IIA (Sudlow's site I), this corroborates the guanidine hydrochloride (GuHCl) induced denaturation of HSA, hydrophobic probe ANS displacement and molecular modeling results. In this work, the presented binding research extends our knowledge of the binding properties of sulfonylurea herbicides to the important plasma protein HSA. © 2010 Elsevier B.V. All rights reserved.


Ding F.,China Agricultural University | Liu W.,China Agricultural University | Zhang X.,China Agricultural University | Zhang L.,Key Laboratory of Pesticide Chemistry and Application Technology | Sun Y.,China Agricultural University
Colloids and Surfaces B: Biointerfaces | Year: 2010

Metsulfuron-methyl is a sulfonylurea herbicide widely used for broad-leaved weed control in cereals. The binding interaction between metsulfuron-methyl and human serum albumin was elucidated by fluorescence, circular dichroism and molecular modeling. The results showed that the alterations of albumin secondary structure in the presence of herbicide induced the slight unfolding of the polypeptide chain of albumin. Fluorescence data revealed that the fluorescence quenching of albumin by herbicide was the result of the formation of the albumin-herbicide complex and hydrophobic and hydrogen bonds interactions were the dominant intermolecular force in stabilizing the complex. Fluorescence probes studies implied that the binding of herbicide to albumin primarily took place in subdomain IIA (Sudlow's site I), and this also corroborates with molecular modeling simulations. This study highlights for the first time the binding mechanism, specific binding site and binding region of herbicide on albumin at the first time. Therefore, this investigation enriches our information of the interaction of sulfonylurea herbicide to the physiologically protein albumin. Crown Copyright © 2009.

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