Interaction of sanguinarine with double stranded RNA structures.
Interaction of sanguinarine with A-form RNA structures of poly(rI)poly(rC) and poly(rA).poly(rU) has been studied by spectrophotometric, spectrofluorimetric, UV melting profiles, circular dichroism and viscometric analysis. The binding of sanguinarine to A-form duplex RNA structures is characterised by the typical bathochromic and hypochromic effects in the absorption spectrum, increasing steady state fluorescence intensity, an increase in fluorescence quantum yield of sanguinarine, an increase in fluorescence polarization anisotropy, an increase of thermal transition temperature, an increase in the contour length of sonicated rod-like RNA structure and perturbation in circular dichroic spectrum. Scatchard analysis indicates that sanguinarine binds to each polymer in a non-cooperative manner. Comparative binding parameters determined from absorbance titration by Scatchard analysis, employing the excluded site model, indicate a higher binding affinity of sanguinarine to poly(rI).poly(rC) structure than to poly(rA).poly(rU) structure. On the basis of these observations, it is concluded that the alkaloid binds to both the RNA structures by a mechanism of intercalation.
Biophysical Chemistry Laboratory, Indian Institute of Chemical Biology, Kolkata 700 032.
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Maiti
D016880:Anisotropy; D000890:Anti-Infective Agents / Q000737:chemistry; D053119:Benzophenanthridines / Q000737:chemistry*; D002942:Circular Dichroism / Q000379:methods; D057446:Hydrodynamics; D007546:Isoquinolines / Q000737:chemistry*; D007700:Kinetics; D008856:Microscopy, Fluorescence / Q000379:methods; D008956:Models, Chemical; D008968:Molecular Conformation; D011485:Protein Binding; D012330:RNA, Double-Stranded / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D014783:Viscosity
D000890:Anti-Infective Agents; D053119:Benzophenanthridines; D007546:Isoquinolines; D012330:RNA, Double-Stranded; C005705:sanguinarine