Specific binding and self-structure induction to poly(A) by the cytotoxic plant alkaloid sanguinarine

• Published in: Biochimica et biophysica acta Vol. 1770; no. 9; pp. 1419 - 1426
• Main Authors: Giri, Prabal, Kumar, Gopinatha Suresh
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2007
• Subjects: Alkaloids - chemistry; Benzophenanthridines - chemistry; Calorimetry, Differential Scanning; Circular Dichroism; Isoquinolines - chemistry; Poly A - chemistry; poly(A); Sanguinarine; Self-structure formation; Specific binding; Spectroscopy; Thermodynamics; T m; CD; Spectroscopy; RNA; D/P; poly(C).poly(G); P/ D; poly(A); Sanguinarine; Self-structure formation; Cp; Specific binding; poly(C); poly(dA); Thermodynamics; t-RNA; HIV; DSC; DNA; ITC; HCV; GC; poly(U); PAP
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2007.05.005

The cytotoxic plant alkaloid sanguinarine was found to bind preferentially and strongly to single stranded poly(A) with an association constant (K a) in the range 3.6–4.6 × 10 6 M − 1 in comparison to several nucleic acids. The binding induced unique self-structure formation in poly(A) that showed cooperative melting transition in circular dichroism, absorbance, and differential scanning calorimetry studies. The alkaloid binding was characterized to be intercalation as revealed from fluorescence quenching experiments and was predominantly enthalpy driven as revealed from isothermal titration calorimetry. Sanguinarine is the first and only natural product so far known to induce a self-structure formation in poly(A).