Rigid spin-labeled nucleoside C: a nonperturbing EPR probe of nucleic acid conformation.

ABSTRACT: Rigid spin-labeled nucleoside C, an analog of deoxycytidine that base-pairs with deoxyguanosine, was incorporated into DNA oligomers by chemical synthesis. Thermal denaturation experiments and circular dichroism (CD) measurements showed that C has a negligible effect on DNA duplex stability and conformation. Nucleoside C was incorporated into several positions within single-stranded DNA oligomers that can adopt two hairpin conformations of similar energy, each of which contains a four-base loop. The relative mobility of nucleotides in the alternating C/G hairpin loops, 5'-d(GCGC) and 5'-d(CGCG), was determined by electron paramagnetic resonance (EPR) spectroscopy. The most mobile nucleotide in the loop is the second one from the 5'-end, followed by the third, first and fourth nucleotides,

SUBMITTER: Cekan P 

PROVIDER: S-EPMC2566876 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature