Intermolecular 'cross-torque': the N4-cytosine propargyl residue is rotated to the 'CH'-edge as a result of Watson-Crick interaction.

ABSTRACT: Propargyl groups are attractive functional groups for labeling purposes, as they allow CuAAC-mediated bioconjugation. Their size minimally exceeds that of a methyl group, the latter being frequent in natural nucleotide modifications. To understand under which circumstances propargyl-containing oligodeoxynucleotides preserve base pairing, we focused on the exocyclic amine of cytidine. Residues attached to the exocyclic N4 may orient away from or toward the Watson-Crick face, ensuing dramatic alteration of base pairing properties. ROESY-NMR experiments suggest a uniform orientation toward the Watson-Crick face of N(4)-propargyl residues in derivatives of both deoxycytidine and 5-methyl-deoxycytidine. In oligodeoxynucleotides, however, UV-melting indicated that N(4)-propargyl-deoxycytidine un

SUBMITTER: Domingo O 

PROVIDER: S-EPMC4477647 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature