A view of DNA short sequences rich in guanines like potassium biosensor.

Bruni L., Manghi M., Croci S.
  Giovedì 14/09   09:00 - 11:30   Aula A209   V - Biofisica e fisica medica
Pu23 and Pu27 are DNA sequences that could work as $K^{+}$ biosensor, since in the presence of $K^{+}$ and/or $Na^{+}$ they fold accordingly to a G-quadruplex structure. This is a DNA secondary structure where more tetrads, made of four paired guanines, are stacked on each other. The specificity of the biosensor relies on a higher G4 affinity for $Na^{+}$ with respect to $Na^{+}$. The biosensor activity of Pu27 and Pu23 are analyzed in the presence of DMEM and DMEM treated with 5 mM K:D-rib, a water solution of D-ribose and $KHCO_{3}$$. In addition, it is described how titrations with NaCl and KCl give details concerning G4 changes when $K^{+}/Na^{+}$ concentrations independently vary.