Adducts do not Destabilize DNA and are Resistant to NER

Why the trans-anti-B[c]Ph-NE-dA and Related Fjord Region N6-dA Adducts do not Destabilize DNA and are Resistant to NER 

In summary, our hypothesis is that the increased polycyclic aromatic ring-base stacking interactions in the fjord region PAH diol epoxide-N -dA adducts stabilize the duplexes and inhibit the extent of strand opening in XPC/HR23B complexes that is critically important for successful NER [38], possibly by preventing the flipping out of nucleotides from the complementary strand. 

Dependence of NER of the 10S [+)-trans-a nti-B[a]P- N2-dC Adduct on Base Sequence Context 

We first consider why base sequence effects can affect the thermodynamic stabilities of double-stranded DNA. The neighboring base-base stacking energies have been analyzed in detail (e.g., see [116, 117]). These interactions are base sequence dependent because of potential steric clashes and electrostatic effects between the 

while the 5 -GT step is less flexible than the TG step [121] and bends slightly into the minor groove [122]. The stacking enthalpies of the TG, TA, and AT dinucleotide steps are lower than those of the CG and GC steps. We found that the bending associated with trans-anti-B[a]P-N2-dG adducts in oligonucleotides can be well accounted for in terms of such a dinucleotide step model [123], 

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