Complementary intrastrand nucleobase

Intercalation between complementary intrastrand nucleobases (type III) shows an intrahelical disposition of (i) in the case of A-T chelation, bindings appear at Ni adenine and N3 thymine (ii) in the case of the G-C chelation, the bindings appear at Ni guanine and N3 cytosine (Figure 7.6). The first approach is characteristic for Hg ", and the second for Cu " and Cd ". The binding is also possible to N7 guanine, N3 cytosine and to O from Cg, respectively C2. 

By B1-B2, we denote intrastrand coupling between nucleobases Bi and B2, arranged along 5 -Bi-B2-3. Referring to bases of the opposite strand, complementary to B as bj (Scheme 1), we shall designate the two different con-... 

A very interesting aspect of platinum-DNA interactions concerns the nature of the resulting adducts and their relative quantities. Due to the bifunctional nature of cis-Pt, several types of adducts in the DNA can be expected to be formed, to be distinguished in (1) interstrand chelates (binding of two nucleobases that are each positioned in one of the complementary DNA strands), (2) intrastrand chelates (binding of two nucleobases within the same DNA strands), (3) intrabase chelates (binding to two different atoms in one base), and (4) DNA-protein cross-links. 

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