Exploring the interaction of phenothiazinium dyes methylene blue, new methylene blue, azure A and azure B with tRNAPhe: spectroscopic, thermodynamic, voltammetric and molecular modeling approach

摘要: This study focuses on the understanding of interaction phenothiazinium dyes methylene blue (MB), new (NMB), azure A (AZA) and B (AZB) with tRNAPhe particular emphasis deciphering mode energetics binding. Strong intercalative binding to was observed for MB, NMB AZB, bound by a partial mode. AZA has shown groove characteristics. From spectroscopic studies affinity values order 105 M-1 were deduced these dyes; trend varied as MB > AZB AZA. The characterized an increase thermal melting temperatures perturbation in circular dichroism spectrum tRNA. All acquired optical activity upon predominantly entropy driven favorable enthalpy term that increased temperature all cases. Dissection Gibbs energy polyelectrolytic non-polyelectrolytic terms revealed major role non-electrostatic forces small but significant heat capacity changes enthalpy-entropy compensation phenomenon confirmed involvement multiple weak non-covalent driving interaction. from quenching, viscosity cyclic voltammetric results. Using density functional theory, ground state optimized structures calculated provide insight into theoretical docking correlate experimental approaches. modeling results verified location well complexation. may insights structure-activity relationship useful design effective RNA targeted therapeutic agents.