Effect of sequence and metal ions on UVB-induced anti cyclobutane pyrimidine dimer formation in human telomeric DNA sequenceNucleic Acids Research
Article VersionPublisher's PDF
AbstractIrradiation of G-quadruplex forming human telomeric DNA with ultraviolet B (UVB) light results in the formation of anti cyclobutane pyrimidine dimers (CPDs) between loop 1 and loop 3 in the presence of potassium ions but not sodium ions. This was unexpected because the sequences involved favor the nonphotoreactive hybrid conformations in K+ solution, whereas a potentially photoreactive basket conformation is favored in Na+ solution. To account for these contradictory results, it was proposed that the loops are too far apart in the basket conformation in Na+ solution but close enough in a two G-tetrad basket-like form 3 conformation that can form in K+ solution. In the current study, Na+ was still found to inhibit anti CPD formation in sequences designed to stabilize the form 3 conformation. Furthermore, anti CPD formation in K+ solution was slower for the sequence previously shown to exist primarily in the proposed photoreactive form 3 conformation than the sequence shown to exist primarily in a nonphotoreactive hybrid conformation. These results suggest that the form 3 conformation is not the principal photoreactive conformation, and that G-quadruplexes in K+ solution are dynamic and able to access photoreactive conformations more easily than in Na+ solution.
Published CitationSmith, J. E., Lu, C., Taylor, J.-S. Effect of sequence and metal ions on UVB-induced anti cyclobutane pyrimidine dimer formation in human telomeric DNA sequences. Nucleic Acids Research 2014 42 (8), 5007-5019. DOI: 10.1093/nar/gku163
Citation InformationJillian E. Smith-Carpenter, Chen Lu and John-Stephen Taylor. "Effect of sequence and metal ions on UVB-induced anti cyclobutane pyrimidine dimer formation in human telomeric DNA sequence" Nucleic Acids Research Vol. 42 Iss. 8 (2014)
Available at: http://works.bepress.com/jillian-smith-carpenter/2/