Abstract 2155 Calcium-Dependent Chemiluminescence Catalyzed by a G-Triplex DNA from the c-MYC Promoter

Certain DNA structures (DNAzymes) have been shown to catalyze chemical and biochemical reactions. One class of DNAzymes mimic peroxidase and catalyze the oxidation of luminol or ABTS in the presence of H2O2 and hemin. These peroxidase-mimicking DNAzymes consist of G-quadruplex structures stabilized by base stacking, hydrogen bonding, and metal coordination, which provide a suitable hydrophobic hemin binding pocket that contributes to oxidation enhancement. G-triplex DNA structures, which are characterized by G:G:G triads, also stabilized by base stacking, hydrogen bonding, and metal coordination, were originally identified as folding intermediates for G-quadruplexes. More recently, certain truncated G-quadruplex forming sequences have been shown to form stable G-triplex structures; although, the "rules" for which sequences fold into stable G-triplexes are not well defined. While G-quadruplex-based peroxidase mimicking DNAzymes have been employed in a number of sensor designs, there have been no examples of chemiluminescence-based DNAzymes based on G-triplex motifs. Here we describe the identification of a G-triplex forming sequence in the c-MYC promoter using CD spectroscopy and UV Tm measurements and show that this G-triplex catalyzes the chemiluminescent oxidation of luminol. Furthermore, we show that the chemiluminescence catalyzed by this G-triplex DNA is calcium ion-dependent, demonstrating the prospects of chemiluminescence biosensors based on G-triplex DNA motifs. Part of this work was funded by NSF Grant DMR-2122041, Partnership for Research and Education in Materials (PREM)