Stabilization of a G-Quadruplex from Unfolding by Replication Protein A Using Potassium and the Porphyrin TMPyP4

Table 1

Spectroscopic melting parameters and RPA unfolding of Gq23 in various conditions.

Sample conditions		260 nm		292 nm		RPA^a	RPA-CDE^a-core
	𝑇𝑀^b° C	TM °C	Δ𝐻VH kcal	TM °C	Δ𝐻VH kcal
(1) Na^+				40	23	++	++
(2) K^+		66	32	57	35	+	+
(3) TMPyP4 + Na^+	<45					+	+
(4) TMPyP4 + K^+				40/80^c	78/58	+	−
(5) Telomestatin + Na^+	<45					++	++
(6) Telomestatin + K^+				60	38	+	+

a++ complete unfolding, + partial unfolding, − no unfolding detected.
bEstimated from their CD spectra at several temperatures.
cMelting curve was biphasic.