Studies on Trinucleotides

The NMR approach has been extensively used for oligonucleotide complexes and allows the study of the effect of different sequences on the overall reaction. Thus, with the trinucleotide d(CpGpG), the GpG sequence adopts the configuration expected of the dinucleotide but the cytosine ring still stacks on the neighboring guanine, despite the fact that the sugar of the base has the N-conformation [90]. 

However, since a molecular explanation of the inherent cytotoxicity of trans-complcxQS cannot include an intrastrand link between adjacent bases, the 1,3-link as demonstrated by these studies presents a viable structural alternative. Is the difference in cis and trans, then, a reflection of a kinetic difference The trans-isomer can form, in principle, an intrastrand link, but more slowly than the cr isomer. The original monoadducts may be excised more efficiently or, indeed, the trans-complex itself may be sequestered more readily. 

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