Cyanine Dyes Targeting G-quadruplex DNA: Significance in Sequence and Conformation Selectivity

Small molecules interacting with DNA is an emerging theme in scientific research due to its specificity and minimal side-effect. Moreover, a large amount of research has been done on finding compounds that can stabilize G-quadruplex DNA, a non-canonical secondary DNA structure, to inhibit cancerous cell proliferation. G-quadruplex DNA is found in the guanine-rich region of the chromosome that has an important role in protecting chromosomes from unwinding, participate in gene expression, contribute in the control replication of cells and more. In this research, rationally designed, synthetic cyanine dye derivatives, which were tested under physiologically relevant conditions, were found to selectively bind to G-quadruplex over duplex DNA and are favored to one structure over another. The interactions were observed using UVvis thermal melting, fluorescence titration, circular dichroism titration, and surface plasmon resonance analysis. For fluorescence and selectivity properties, cyanine dyes, therefore, have the potential to become the detections and/or therapeutic drugs to target cancers and many other fatal diseases. INDEX WORDS: G-quadruplex DNA, Cyanine dyes, UV-vis thermal melting, Fluorescence, Circular dichroism, Surface plasmon resonance, cMyc, hTel CYANINE DYES TARGETING G-QUADRUPLEX DNA: SIGNIFICANCE IN SEQUENCE AND CONFORMATION SELECTIVITY