Year: 2020
Type: article
Abstract: Increase in turn-on was best achieved with addition of potassium salt.The size and charge of a potassium ion make it ideal for fitting in the center of each tetrad and coordinating the electronegative groups in the center when the quadruplex is in a parallel confirmation.Sodium ion, due to its smaller atomic radius, is ideal for coordination of an anti-parallel G-quadruplex; no fluorescence dependence on sodium ion concentration was observed.These trends suggest the hybrid Gquadruplex leans in favor of a parallel orientation, and the presence of potassium increases the switching from hybrid to parallel.Magnesium ion does not coordinate G-tetrads well and has even been shown to destabilize G-quadruplexes.However, in smaller concentrations it can stabilize the DNA backbone of the aptamer.Further experimentation by other team members varied individual salt concentrations alone in Tris buffer (pH 7.4).A smaller concentration of 25 mM magnesium was found to be optimal for turn-on.It was confirmed that potassium ion is essential for binding and fluorescent signal and that sodium ion has no effect.The optimal buffer composition that was created and used for mutational analysis was 20 mM Tris HCl pH 7.4, 20 mM potassium chloride, and 25 mM magnesium chloride.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3034937720