| Institution: | 1. Instituto de Química Física Rocasolano, CSIC, Serrano, 119, 28006 Madrid, Spain;2. Department of Food, Environmental and Nutritional Sciences (DEFENS), Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy;3. Dept. of Chemical Engineering and Analytical Chemistry, University of Barcelona, Marti i Franquès 1, 08028 Barcelona, Spain
BIOESTRAN associated unit UB-CSIC, 08028 Barcelona, Spain;4. Institute for Advanced Chemistry of Catalonia (IQAC-CSIC) CIBER-BBN, Jordi, Girona 18–26, 08034 Barcelona, Spain |
| Abstract: | We report the structural effect of 2'-deoxy-2',2'-difluorocytidine (dFdC) insertions in the DNA strand of a DNA : RNA hybrid duplex and in a self-complementary DNA : DNA duplex. In both cases, the modification slightly destabilizes the duplex and provokes minor local distortions that are more pronounced in the case of the DNA : RNA hybrid. Analysis of the solution structures determined by NMR methods show that dFdC is an adaptable derivative that adopts North type sugar conformation when inserted in pure DNA, or a South sugar conformation in the context of DNA : RNA hybrids. In this latter context, South sugar pucker favors the formation of a 2'F⋅⋅H8 attractive interaction with a neighboring purine, which compensates the destabilizing effect of base pair distortions. These interactions share some features with pseudohydrogen bonds described previously in other nucleic acids structures with fluorine modified sugars. |
