Protocol for circular dichroism spectral analysis of the thermal stability of CpG-methylated quadruplex structures

G-quadruplex and intercalated motif are quadruplex structures of which sequences are enriched in promoters. Here, we present a protocol for circular dichroism spectral analysis of the thermal stability of CpG-methylated quadruplex structures. We describe steps for preparing the oligonucleotide sample, measuring the circular dichroism spectrum of methylated quadruplex structures, and calculating thermodynamic parameters using Python 3. For complete details on the use and execution of this protocol, please refer to Kimura et al.¹.