Fluorescence of sanguinarine: spectral changes on interaction with amino acids

Abstract

The quaternary isoquinoline alkaloid, sanguinarine (SG) exhibits a wide range of biological activities. This study examines spectral changes expected from SG binding to proteins. Fluorescence spectra of the cationic form of sanguinarine (SG(+)) are sensitive to environment polarity. On the other hand, spectra of the neutral form of sanguinarine, pseudobase (SGOH) and dihydrosanguinarine (DHSG, the first metabolite of SG) exhibit higher sensitivity to the ability of solvent to form a solute-to-solvent hydrogen bonds. Interaction with cysteine has been the only mode of SG binding to enzymes that has been considered so far. In reality, our experiments have revealed spectral changes on specific interactions of SG(+) with Cys, Glu and Tyr in the protic environment and with Arg and Glu in the aprotic environment. We have also detected interactions of SGOH with Cys in the protic environment and with Cys, Glu and Lys in the aprotic environment. The DHSG spectra were only altered in the presence of the Cys analog in the protic environment. We have also demonstrated that spectral change analysis can aid investigation of SG/DHSG interactions with proteins and we were able to identify SG(+)-binding site on Na(+)/K(+)-ATPase.

DNA Abasic Site-Selective Enhancement of Sanguinarine Fluorescence with a Large Emission Shift

“…Besides its interaction with proteins [29] and amino acids [30], one of the potential antitumor activities of SG is believed to result from its highly specific binding to many types of nucleic acid structures and subsequent modification of the genetic information [31]. SG exhibits a pH-dependent structure equilibrium in aqueous solution between the positively charged iminium (in the pH rang 1.0–6.0) and the neutral alkanolamine (in the pH rang 8.5–11.0) forms (Figure 1) [31], [32].…”

Surface-Enhanced Raman Spectroscopy (SERS) Tracking of Chelerythrine, a Na+/K+Pump Inhibitor, into Cytosol and Plasma Membrane Fractions of Human Lens Epithelial Cell Cultures

“…The amino acid sequence ARAAEILARDGPN of the first putative CET binding site resides in the A domain of the NKP and has two arginine (R) residues. Interestingly, fluorescence studies suggest interaction of R residues with sanguinarines, however, in the carboxy (C)-terminus of the NKP [18]. Moreover, sequence homologies of the NKP BH1-like motifs found in all P-type ATPases suggest other cellular metabolic pathways can be influenced by the presence of CET [10].…”

Phytochemical and biological research of Chelidonieae pharmaceutical resources

“…Chelerythrine possesses powerful anticariogenic potential and can be used for prevention of dental caries. Sanguinarine (+) binding site on Na + /K + -ATPase has been identified (Janovská et al, 2010). Sanguinarine (+) binding site on Na + /K + -ATPase has been identified (Janovská et al, 2010).…”