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Structural Effects of Incorporation of 2'‐Deoxy‐2'2'‐Difluorodeoxycytidine (Gemcitabine) in A‐ and B‐Form Duplexes
Author(s) -
Cabrero Cristina,
MartínPintado Nerea,
Mazzini Stefania,
Gargallo Raimundo,
Eritja Ramon,
Aviñó Anna,
González Carlos
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202100503
Subject(s) - dna , duplex (building) , rna , chemistry , nucleic acid , base pair , context (archaeology) , stereochemistry , sugar , biochemistry , crystallography , biology , gene , paleontology
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.