UV thermal denaturation studies

Oligonucleotides were suspended in 1 ml of buffer, heated at 95°C for 10 min, slowly cooled to room temperature and incubated at 4°C overnight. The samples were then degassed on the speed-vacuum concentrator for 2 min. UV thermal denaturation data were acquired with a Varian CARY Model 3E Spectrophotometer Varian fitted with a 12-sample thermostated cell block and a temperature controller, with absorbance measured at 260 nm and a heating rate of 0.5°C/min. The melting temperature (T_m) was calculated as the maximum of the first derivative according to the method of Puglisi and Tinoco (17). All data analysis were performed with Microsoft Excel^™.