RT info:eu-repo/semantics/article T1 Alcian blue pyridine variant interaction with DNA and RNA polynucleotides and G-quadruplexes: changes in the binding features for different biosubstrates A1 Macii, Francesca A1 Pérez Arnáiz, Cristina A1 Arrico, Lorenzo A1 Busto Vázquez, Natalia A1 García Ruiz, Begoña A1 Biver, Tarita K1 Groove binding K1 Partial intercalation K1 Helix conformation K1 Enthalpy-entropy compensation K1 Anti-parallel K1 Hybrid K1 Química inorgánica K1 Chemistry, Inorganic K1 Bioquímica K1 Biochemistry AB This work concerns an analysis of the binding mechanism of a copper phthalocyanine (Alcian Blue-tetrakis(methylpyridinium) chloride, ABTP) to natural calf thymus DNA, G-quadruplexes (G4) and synthetic RNA polynucleotides in the form of double polyriboadenylic·polyribouridylic acid (poly(A)·poly(U)) or triple strands polyriboadenylic·2polyribouridylic acid (poly(A)·2poly(U)). ABTP is a well know dye that might undergo novel applications, but its interaction with DNA is scarcely studied and we lack information on possible RNA or G4 binding. This might be related to system complexity due to the presence of supramolecular dye-dye aggregates. Despite this, we show here that apparent parameters can be calculated, which provide information on the binding mechanism. Absorbance titrations in the presence of biosubstrate excess, melting and circular dichroism experiments show that ABTP binds to both RNAs and DNA. External/groove binding is the main feature for RNAs, whereas partial intercalation is the major binging mode for DNA. ABTP externally binds to both hybrid, parallel and anti-parallel G4s but seem to show a slightly different binding mode and a preference for anti-parallel structures. The thermodynamic features of the different systems are also discussed in the frame of the enthalpy-entropy compensation phenomenon. PB Elsevier SN 0162-0134 YR 2020 FD 2020-11 LK http://hdl.handle.net/10259/5475 UL http://hdl.handle.net/10259/5475 LA eng NO la Caixa” Foundation (LCF/PR/PR12/11070003), Ministerio de Ciencia, Innovación y Universidades-FEDER (RTI2018- 102040-B-100) and Junta de Castilla y León-FEDER (BU305P18) DS Repositorio Institucional de la Universidad de Burgos RD 29-mar-2024