Inhibition of HIV Replication by Cyclic and Hairpin PNAs Targeting the HIV-1 TAR RNA Loop

Table 1

Melting temperatures (𝑇_m^∘C) of Mini-TAR/PNA complexes and of hairpin PNAs alone.

PNA	Mini-TAR/PNA complex 𝑇m (°C)	Hairpin PNA alone 𝑇m(°C)
3	<10	—
4	45.1 ± 0.6	73.0 ± 0.3
5	52.4 ± 0.2	84.0 ± 0.5
6	38.4 ± 0.3	29.8 ± 0.6

Experiments were performed in R buffer (pH 7.3) containing cacodylate (20 mM), NaCl (20 mM), KCl (140 mM), and MgCl2 (0.3 mM). Individual PNAs and mini-TAR (2 μM final concentration of each) were gently mixed and incubated at 5°C for 1 h. Thermal denaturation was achieved by increasing the temperature from 5°C to 90°C at the linear gradient of 0.4°C/min. The changes in UV absorption at 260 nm were monitored. Melting temperatures (𝑇_m) were determined as the maximum of the first derivative of the melting curves.