The investigation of the interaction between ribavirin and bovine serum albumin by spectroscopic methods

Abstract

The interaction between ribavirin (RIB) with bovine serum albumin (BSA) has been investigated by fluorescence quenching technique in combination with UV-vis absorption and circular dichroism (CD) spectroscopies under the simulative physiological conditions. The quenching of BSA fluorescence by RIB was found to be a result of the formation of RIB-BSA complex. The binding constants and the number of binding sites were calculated at three different temperatures. The values of thermodynamic parameters ∆H, ∆S, ∆G at different temperatures indicate that hydrophobic and hydrogen bonds played important roles for RIB-BSA association. The binding distance r was obtained according to the theory of Förster's non-radiation energy transfer. The displacement experiments was performed for identifying the location of the binding site of RIB on BSA. The effects of common ions on the binding constant of RIB and BSA were also examined. Finally, the conformational changes of BSA in the presence of RIB were also analyzed by CD spectra and Synchronous fluorescence spectra.

Interaction of ergosterol with bovine serum albumin and human serum albumin by spectroscopic analysis

“…In Fig. 6(A, b, B, b), the maximum emission wavelength of Trp residues did not have a significant shift in the presence of ergosterol, suggesting that the microenvironments around Trp residues had no discernable change during the interaction of ergosterol with BSA/HSA [28]. However, it could be seen from Fig.…”

“…However, it could be seen from Fig. 7 that the strong fluorescence quenching of Trp residues decreased 57.2/58.6 % in fluorescence intensities of BSA/ HSA with the addition of ergosterol, indicating that ergosterol reached subdomain IIA, where the only one Trp residue (Trp-212/Trp-214) on BSA/HSA was located [28,30]. There was a large hydrophobic cavity in subdomain IIA which many drugs could bind to them.…”

“…The shift in the position of maximum emission wavelength reflects the change of the polarity around chromophore molecule [27]. When the wavelength interval (Dk) between the excitation and emission wavelength is stabilized at 15 and 60 nm, the synchronous fluorescence offers the characteristics of Tyr and Trp residues [28]. The fluorescence spectra of Tyr and Trp residues on BSA/HSA at various concentrations of ergosterol were shown in Fig.…”

Studies on the interaction between scopoletin and two serum albumins by spectroscopic methods

“…In Fig.8(A,b and B, b), the maximum emission wavelength of Trp residues did not have a significant shift in the presence of scopoletin, which suggested that the microenvironment around Trp residues had no discernable change during the interaction of scopoletin with BSA/ HSA [38]. However, It could be seen from Fig.…”

“…The shift in maximum emission wavelength reflects the change of the polarity around chromophore molecule. When Dl is stabilized at 15 and 60 nm, the synchronous fluorescence offers the characteristics of Tyr and Trp residues, respectively [38]. The fluorescence spectra of Tyr and Trp residues on BSA/HSA at various concentrations of scopoletin were shown in Fig.…”