title: The interaction of plant-growth regulators with serum albumin: molecular modeling and spectroscopic methods.
abstract: The affinity between two plant-growth regulators (PGRs) and human serum albumin (HSA) was investigated by molecular modeling techniques and spectroscopic methods. The results of molecular modeling simulations revealed that paclobutrazol (PAC) could bind on both site I and site II in HSA where the interaction was easier, while uniconazole (UNI) could not bind with HSA. Furthermore, the results of fluorescence spectroscopy, three-dimensional (3D) fluorescence spectroscopy and circular dichroism (CD) spectroscopy suggested that PAC had a strong ability to quench the intrinsic fluorescence of HSA. The binding affinity (Kb) and the amounts of binding sites (n) between PAC and HSA at 291 K were estimated as 2.37×10(5) mol L(-1) and 1, respectively, which confirm that PAC mainly binds on site II of HSA. An apparent distance between the Trp214 and PAC was 4.41 nm. Additionally, the binding of PAC induced the conformational changes of disulfide bridges of HSA with the decrease of α-helix content. These studies provide more information on the potential toxicological effects and environmental risk assessment of PGRs.
authors.affiliation: College of Sciences, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: dshiney2004@yahoo.com.cn.
authors.forename: Sheying
authors.initials: S
authors.lastname: Dong
authors.affiliation: College of Sciences, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Zhiqin
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Sciences, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Shi
authors.affiliation: College of Sciences, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Guiqi
authors.initials: G
authors.lastname: Huang
authors.affiliation: College of Sciences, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Shuangli
authors.initials: S
authors.lastname: Chen
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Tinglin
authors.initials: T
authors.lastname: Huang
mesh_terms: D002942:Circular Dichroism; D008958:Models, Molecular; D010937:Plant Growth Regulators / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D010937:Plant Growth Regulators; D012709:Serum Albumin
keywords: Human serum albumin (HSA); Interaction molecular modeling; Plant-growth regulators (PGRs); Spectroscopic methods