The interaction between BLF and BSA and impact in interaction of RT-BSA-BLF system / 药学学报

The binding of rhaponticin to bovine serum albumin (BSA)-bovine lactoferrin (BLF) and the factors that affect BSA-BLF interaction have been studied by fluorescence spectroscopy and Fourier transform infrared spectroscopy. In the fluorescence experiment, RT quenched the fluorescence intensity of mixed proteome and the maximum emission wavelength of BSA, BLF and BSA-BLF proteins system. RT caused obvious red-shift fluorescence for an interaction between RT and proteome. The interaction between RT and proteome was impacted by single-component protein molecular interactions and the interaction between RT-BSA and RT-BLF, the microenvironment of solutions were the factors impacting the interactions between RT and proteome, which impacted quantitative expression of the general environment micro environmental factors. In the Fourier transform infrared spectroscopy, the secondary conformation of protein molecules of single component in the protein group were changed, and the difference of the molecules' structure was responsible for the differences in the molecular conformation changes. The molecules' interaction in the single-component protein affected secondary conformation of the proteins' molecule. The proteins' concentration ratio and the interaction were different in degree of molecular conformational change. These data demonstrates an example of combination of fluorescence spectrum experiment with Fourier transform infrared spectroscopy in the study of protein structura.

Binding mechanism of rhaponticin and human serum albumin / 药学学报

The interaction mechanism between rhaponticin (RT) and human serum albumin (HSA) has been studied by fluorescence spectroscopy and absorbance spectra. The mediation effect that the metal ions took part in the interaction has also been discussed in this paper. Based on different theoretical models of fluorescence quenching, the binding constant (K) and binding sites (n) of the interaction were determined and analyzed comparatively. The quenching mechanism of the binding reaction has also been discussed. The binding distance (r) and energy-transfer efficiency (E) between RT/RT-Co(II)/RT-Ni(II) and HSA were also obtained by virtue of the Förster theory of non-radiation energy transfer. The effect of RT acting on the HSA's conformation was analyzed by synchronous fluorescence spectroscopy. The result showed that the result calculated by different theoretical models is generally equivalent and RT bound HSA strongly by forming stable complex, which indicates that HSA under physiological conditions can act as a carrier for RT to be transported to exert effects. The microconformation of HSA changed significantly due to hydrophobicity change in the chemical environment of some fluorescence chromophores in the subdomain IIA and IIB of HSA. Metal ions Co(II) and Ni(II) can mediate RT-HSA interaction, making the binding of the drug to protein stronger, which indicates that Co(II) and Ni(II) can enhance rhaponticin's medical efficacy under physiological conditions.